MXPA06003361A - A method of modulating cell survival, differentiation and/or synaptic plasticity - Google Patents

Abstract

The present invention relates to a method of modulating differentiation, adhesion and/or survival of the neural cell adhesion molecule (NCAM) presenting cells by providing compounds capable of modulating the interaction between the Ig1, Ig2 and/or Ig3 modules of NCAM. The invention provides candidate compounds capable of modulating the interaction between the Ig1, Ig2 and/or Ig3 modules of NCAM by using methods for screening and testing described in the application. The invention further relates to pharmaceutical compositions comprising compounds capable of modulating the interaction between the Ig1, Ig2 and/or Ig3 modules of NCAM and to use of the pharmaceutical compositions and compounds for the modulation of differentiation, adhesion and/or survival of NCAM presenting cells.

Description

METHOD FOR MODULAR SYNAPTIC PLASTICITY, DIFFERENTIATION AND / OR CELLULAR SURVIVAL Field of the Invention The present invention relates to a method for modulating cell differentiation and / or survival by providing compounds capable of modulating the interaction between two individual neural cell adhesion molecules (NCAMs). The invention further relates to a method for detecting candidate compounds capable of modulating the interaction between the Igl, Ig2 and / or Ig3 modules of two individual? CAMs. The invention also relates to the use of the identified candidate compounds for the manufacture of a medicament. BACKGROUND OF THE INVENTION The neural cell adhesion molecule, NCAM, measured cell-cell adhesion by homophilic binding (? CAM-? CAM). NCAM plays a key role in neural development, neuronal differentiation and synaptic plasticity, including learning and memory consolidation. Intercellular interactions play a crucial role in a wide variety of biological processes, including migration, survival and cell differentiation. These phenomena depend on the protein recognition in the REF: 171385 cell surface mediated by cell-cell adhesion molecules (CAM). The neural cell adhesion molecule, NCAM, originally described as a synaptic membrane protein (Jorgensen and Bock, 1974), and subsequently shown as measuring cell-cell adhesion was the first identified mammalian cell adhesion molecule. The? CAM corresponds to the immunoglobulin (Ig) superfamily. The alternative splicing of the mRNA and the post-transductional modifications generate a large number of? CAM isoforms. The three main NCAM isoforms have identical extracellular parts consisting of five Ig modules and two fibronectin type III modules. It is known that? CAM measured cell-cell and cell-substrate adhesion independent of Ca2 + through homophilic interactions (union of? CAM to? CAM) and heterophiles (binding of? CAM to other molecules) (Berezin et al., 2000). It has been shown that different CAM modules perform different functions. The? CAM binds to several components of the extracellular matrix such as heparin / heparan sulfate, chondroitin sulfate proteoglycans and different types of collagen. The heparin binding sequence is located in the Ig2 module. The? CAM also binds to the Ll molecule of adhesion to neural cells. This interaction is believed to take place between the fourth Ig module of the? CAM and an oligomannosidic portion expressed in Ll. Despite extensive studies, the precise mechanism of homologous NCAM binding remains unclear, and the published results are to some degree contradictory. Originally it was reported that the homologous binding of NCAM depends on the anti-parallel interaction between the Ig3 modules of two opposite NCAM molecules. Cell aggregation experiments performed on mouse L cells expressing chicken NCAM with deletions of 'different Ig modules indicated an involvement of the Ig3 module. Subsequently, using microspheres coated with individual recombinant Ig modules of chicken? CAM, the binding between the Igl and Ig5 modules and between the Ig2 and Ig4 modules was demonstrated, while the Ig3 coated microspheres exhibited strong autoaggregation (Ranheim et al. , nineteen ninety six) . However, a study by Atkins et al., (2001) of the solution structure of the Ig3 module of the Chicken CAM that includes ultracentrifugation experiments does not support the suggested dimerization of Ig3. A binding between the recombinant Igl and rat Ig2 modules was demonstrated by means of surface plasmon resonance analysis (Kiselyov et al., 1997). The three-dimensional structures of the individual rat Igl and Ig2 modules, and the chicken Igl module, have been determined by nuclear magnetic resonance (NMR) spectroscopy, which results in the identification of ammonia residues comprised in the homophilic junction. between the Igl and Ig2 modules (Thomsen et al., 1996; Jensen et al., 1999; Atkins et al., 1999). The crystal structure of the Igl-2 fragment of the? CAM provided detailed information of the cross-type Igl-2 dimer, and pointed out the key residues in this interaction, specifically F19 and Y65 (Kasper et al., 2000). Recently, it was shown that a point mutation of F19 (F19S) does not affect cell aggregation mediated by full-length CAM, although the dimerization of the Igl-2-3 fragment, which otherwise takes place in solution, is canceled ( Atkins et al., 2001). Therefore, these results question the Ig3 to Ig3 models (Rao et al., 1992; Ranheim et al., 1996) and Igl to Ig2 (Kiselyov et al., 1997; Kasper et al., 2000) of the homophilic union of? CAM. In this way, the two homologous binding sites of non-overlap of the? CAM have been described in the scientific literature; the binding sites from Ig3 to Ig3 and from Igl to Ig2. Sequences derived from these two sites have shown that they are able to stimulate neurite outgrowth and modulate the adhesion of neural cells (WO03020749, Soroka et al., 2002; Rao et al., 1992; Ranheim et al., 1996). . It has also been shown that peptide sequences, which are capable of binding to the Ig3 to Ig3 binding site, do not interfere with the biological effects mediated by the IgG to Ig2 binding site, and vice versa. This last finding indicates that the homophilic adhesion of NCAM has a much more complex mechanism, than only the mechanism of mechanistic union of two individual molecules of NCAM through multiple homophilic binding sites, and that the implication of one or the other binding site homophilic in a process mediated by NCAM may depend on a particular NCAM environment, such as, for example, the presence of a ligand of either binding site, with the availability of either site for the binding. The present invention provides a method for modulating these processes by providing compounds capable of binding to the Igl, Ig2 and / or Ig3 modules of NCAM through a novel homophilic binding site. Brief Description of the Invention According to the present invention, the provision of ligands directed to different homologous binding sites of NCAM can allow a fine regulation of the involvement of NCAM in molecular mechanisms that are the basis of different processes related to cell plasticity. neural and thus modulation of these processes. Thus, the present invention relates to compounds, which are capable of modulating adhesion, of inducing differentiation, and of promoting regeneration, neuronal plasticity and survival of cells expressing NCAM, and to methods for detecting and using these compounds. In one aspect, the present invention relates to methods for modulating the cellular differentiation and / or difference of the cells that exhibit the neural cell adhesion molecule (NCAM), which comprises: a) providing a candidate compound capable of: ) interact with the Igl module of NCAM, and in this way imitate and / or modulate the interaction between the Igl and Ig3 modules of NCAM, where the modules are of two individual NCAM molecules, and / or ii) interact with the Ig3 module of NCAM, and thus mimic and / or modulate the interaction between the Ig3 and Igl modules of? CAM, where the modules are of two individual NCAM molecules, and / or iii) interact with the NCAM Ig2 module, and this mode mimics the interaction between the Ig2 and Ig3 modules of NCAM, where the modules are of two individual NCAM molecules, and / or iv) interact with the NCAM Ig3 module, and thus mimic and / or modulate the interaction between the modules Ig3 and Ig2 of? CAM, where the modules are of two molecules ? Individual CAMs, and / or v) interact with the Ig2 module of? CAM, and in this way mimic and / or modulate the interaction between the Ig2 and Ig2 modules of NCAM, where the modules are of two individual? CAM molecules. b) providing at least one cell presenting? CAM; c) contacting at least one cell presenting NCAM with the candidate compound, and thereby modulating cell differentiation and / or survival of at least one cell displaying? CAM. In another aspect, the present invention relates to a method for testing a compound if it is capable of modulating the interaction between two individual CAM molecules through a homophilic binding site composed of the Igl, Ig2 and Ig3 molecules of the molecules? CAM modulating the interaction of: i) the Igl module of an individual CAM molecule with the Ig3 module of another individual CAM molecule, and / or ii) the Ig2 module of an individual CAM molecule with the Ig3 module of another molecule "Individual CAM, and / or iii) the Ig2 module of an individual CAM molecule with the Ig2 module of another individual CAM molecule, the method comprising a) providing a compound; b) providing at least one individual fragment of a CAM molecule, wherein the fragment comprises a sequence of consecutive residues of ammonia acids corresponding to the sequence of the Igl-2-3 module of NCAM comprising residues 1 to 289 of the sequence exposed in SEQ. ID. No.: 44, or a fragment of the individual fragment; c) test whether the compound is able to i) interact with the NCL Igl module, and thus mimic and / or modulate the interaction between NCAM Igl and Ig3 modules, where the modules are of the two individual fragments of (b) that interact with each other, and / or ii) interact with the NC3 Ig3 module, and thus mimic and / or modulate the interaction between the Ig3 and IgG modules of NCAM, where the modules are of the two fragments Individuals of (b) interacting with each other, and / or iii) interacting with the NCAM Ig2 module, and thereby mimic the interaction between the NCAM Ig2 and Ig3 modules, wherein the modules are of the two individual fragments of (b) interacting with each other, and / or iv) interacting with the NCAM Ig3 module, and thus mimic and / or modulate the interaction between the IgM and Ig2 modules of NCAM, where the modules are of the two fragments Individuals of (b) that interact with each other, and / or v) interact with the Ig2 module? CAM, and in this way mimic and / or modulate the interaction between the Ig2 and Ig2 modules of NCAM, wherein the modules are of the two individual fragments of (b) that interact with each other, upon contacting the compound with a fragment of (b) ); d) selecting a compound capable of at least one interaction of (c) as a candidate compound capable of modulating the differentiation, adhesion and / or survival of a cell presenting NCAM. In still another aspect, the present invention provides a method for selecting a candidate compound capable of modulating the differentiation, adhesion and / or survival of cells displaying ΔCAM by modulating the interaction of i) the Igl module of an individual ΔCAM molecule with the Ig3 module of another individual CAM molecule, and / or ii) the Ig2 module of an individual CAM molecule with the Ig3 module of another individual CAM molecule, and / or iii) the Ig2 module of a single CAM molecule with the Ig2 module of another single CAM molecule, the method comprising the steps of a) providing a soluble or crystalline polypeptide comprising the Igl-2-3 module of? CAM, b) generating a structural model of the Igl-2- module 3 of? CAM from (a) when using computer modeling techniques; c) evaluate in silicon compounds for the ability to: i) interact with the Igl module of? CAM, and in this way imitate and / or modulate the interaction between the Igl and Ig3 modules of NCAM, where the modules are of two molecules Individual NCAMs, and / or ii) interact with the NCAM Ig3 module, and in this way imitate and / or modulate the interaction between the Ig3 and Igl modules of? CAM, where the modules are of two individual CAM molecules, and / or iii) interact with the Ig2 module of? CAM, and of This mode mimics the interaction between the Ig2 and Ig3 modules of NCAM, where the modules are from two individual CAM molecules, and / or iv) interact with the Ig3 module of? CAM, and in this way imitate and / or modulate the interaction between the Ig3 and Ig2 modules of? CAM, where the modules are of two molecules? individual CAMs, and / or v) interact with the Ig2 module of? CAM, and in this way imitate and / or modulate the interaction between the module Ig2 and Ig2 of? CAM, where the modules are of two individual molecules? CAM, when using the model (s) structure (s) of the Igl-2-3 module of? CAM of (c); d) selecting a candidate compound capable of at least one interaction of (b), and e) testing the candidate compound of (d) in an in vitro or in vivo assay for the ability to modulate cell differentiation, adhesion and / or survival having NCAM, assays comprising at least one cell presenting NCAM, and / or) testing the candidate compound of (d) in an assay comprising evaluating the compound's ability to at least one interaction of (b) by putting in contacting the compound with at least one individual fragment of an NCAM molecule, the fragment comprising a sequence of consecutive residues of ammonia acids corresponding to the sequence of the Igl-2-3 module of NCAM comprising residues 1 to 289 of the exposed sequence in SEQ. ID. No.:44. Thus, it is an object of the present invention to provide a crystal protein comprising the Igl-2-3 module of NCAM and a method for preparing the crystal protein. The invention further provides the compounds capable of i) interacting with the Igl module of NCAM, and thereby mimic and / or modulate the interaction between the Igl and Ig3 modules of NCAM, wherein the modules are of two individual NCAM molecules, and / or ii) interact with the NC3 Ig3 module, and thus mimic and / or modulate the interaction between the Ig3 and Igl modules of NCAM, where the modules are of two individual NCAM molecules, and / or iii) interact with the NCAM Ig2 module, and thus mimic the interaction between the NCAM Ig2 and Ig3 modules, where the modules are of two individual NCAM molecules, and / or iv) interact with the NCAM Ig3 module, and thus imitate and / or modulate the interaction between the Ig3 and Ig2 modules of NCAM, where the modules are of two individual NCAM molecules, and / or v) interact with the Ig2 module of? CAM, and in this way imitate and / or modulate the interaction between the Ig2 and Ig2 modules of? CAM, where the modules s are two individual molecules? CAM. The invention also relates to the use of the compounds selected by the above methods for the manufacture of a medicament and pharmaceutical compositions comprising it. Brief Description of the Figures Figure 1 presents crystallographic data and refinement statistics. Figure 2 presents the coordinates of the atomic structure of the crystal of the Igl-2-3 module. Figures 3A-3B present the crystal structure of the Igl-2-3 fragment of? CAM rat at a resolution of 2.0 A. (Fig. 3A) Stereoscopic structure diagram of Ca with each? O ~ eS3-or residue marked. (Fig. 3B) Ribbon diagram in ß-threads marked according to the nomenclature of the Igl set. Figures 4A-4D show the crystal structure of the NCAM Igl-2-3 fragment revealing four major module-module interactions and two kinds of Igl-2-3 arrays. They show the space filling models of the interacting Igl-2-3 cis-dimers (mediated by Igl-Ig2 binding). The interaction sites Igl to Ig2, Igl to Ig3, Ig2 to Ig2 and Ig2 to Ig3 are indicated by white ellipses. The heparin binding sites of the Ig2 modules (residues 133-148) are indicated by white squares. The arrows indicate the position of the N-linked glycosylation in Asn203 (Asn203 is marked with a white triangle). The terms are denoted by N and C. (Figs 4A, 4B) the cis-dimers mediated by Igl-2 of the Igl-2-3 fragment form a "planar" zipper by the Ig-Ig3-mediated trans-interaction. , which reflect an interaction between NCAM molecules to opposite cells. (Figs 4C, 4D) The cis-dimers of the Igl-2-3 fragment also form a non-symmetric "compact" zipper by trans-interactions from Igl to Ig3 and from Ig2 to Ig2. 2-cis-dimers are retained together by two interactions from Igl to Ig3 (and full ellipses) on one side and an interaction of Ig2 to Ig2 (granulated ellipse) on the opposite side of the zipper.

The views in Figs. 4B and 4D are perpendicular to FIGS. 4A and 4C, respectively. Figures 5A-5D show a focus view of the interaction interfaces in the Igl-2-3 fragment of NCAM. (Fig. 5A) The interaction interface from Igl to Ig2. The Igl and Ig2 modules correspond to two fragments of Igl-2-3 at different intervals that form a cis-dimer of Igl-2-3. (Fig. 5B) The interaction interface from Ig2 to Ig3. (Fig. 5C) The interaction interface of Ig2 to Ig2. (Fig. 5D) The interaction interface from Igl to Ig3. In figs. 5B-5D, the tape representations of the modules of two interacting Igl-2-3 fragments corresponding to different individual Igl-2-3 cis-dimers. The hydrogen bonds are shown as dashed lines. Figures 6A-6G show the effect of the module of Ig3, the peptides Pl-B, P3-DE, P3-G, P3-B and their derivatives, in the outgrowth of neurites of PC12-E2 cells expressing NCAM cultured above a confluent monolayer of fibroblasts transfected with NCAM. (Fig. 6A-6F) Confocal micrographs of PC12-E2 pheochromocytoma cells expressing NCAM cultured above a confluent monolayer of B, D, F L929 fibroblasts transfected with NCAM-140, or A, C, E transfected with vector. Interaction? CAM-? CAM and stimulates neurite outgrowth in PC12-E2 cells cultured above fibroblasts fig. 6A negative to NCAM (LBN) or versus fig. 6B expressing NCAM (L? 7N). The introduction of the recombinant Ig3 module does not affect the PC12-E2 cells cultured in figl 6C fibroblasts transfected with vector but clearly inhibits the outgrowth of neurites in PC12-E2 cells cultured in fibroblasts fig. 6D transfected with? CAM as a result of the disruption of interactions in? CAM-? CAM. In contrast, Ig3mut2 does not affect the PC12-E2 cells cultured in fibroblasts fig. 6E transfected with vector neither inhibits the excrescence fig. 6F of neurites induced by? CAM. The peptides Pl-B, P3-DE and P3-G have comparable inhibitory effects to the effect of Ig3wt C, D whereas the effects of Ig3mutl, peptide P3-B and control peptide Ig3mutl, peptide P3-B are similar to the effect of Ig3mut2 E, F. Bar scale 20 μm. (Figure 6G) The effect of the Ig3 module, peptides Pl-B, P3-DE, P3-G, P3-B, and their derivatives, are shown as percent control, adjusting the difference between the average length of the neurite of PC12-E2 cells cultured in fibroblasts transfected with? CAM-140 and transfected with 100% vector. The results are given as minus ± SEM. * P < 0.05, ** P < 0.01 (compared to the induction of neurite outgrowth of PC12-E2 cells cultured above monolayer of fibroblasts transfected with CAM CAM Figures 7A-7C show schematic representations of "compact", "flat" zipper adhesion complexes and "double" formed by NCAM, as observed in the crystal structure of the NCAM Igl-2-3 fragment.The individual NCAM modules are shown as cylinders.The Ig and FnlII modules are listed by Arabic and Roman numerals. In order to accommodate all seven NCAM extracellular modules, a curve after Ig4 has been introduced according to electron microscopy studies (Hall and Rutishauser, 1987, Becker et al., 1989). of the Igl-2-3 fragment and the distance between the opposing cell membranes (Fig. 7A) The "compact" zippers are stabilized by the interactions Igl to Ig3 and Ig2 to Ig2 among the cis-dimers of Igl-2-3 That originate from two opposite cell membranes. (Fig. 7B) The "flat" zipper is stabilized by the Ig2 to Ig3 interactions between the Igl-2-3 cis-dimers that originate from two opposite cell membranes. (Fig. 7C) The two types of zippers can coexist as observed in the glass and will result in the formation of a double zipper adhesion complex. Figure 8 demonstrates the effect of the P2-CD peptide on the excrescence of CGN neurites grown as individual neurons in primary culture for 24 hours in the presence of different concentrations of the peptide in the growth medium. The length of the neurites is expressed in arbitrary units (AU). The length of the neurites in treated cultures is compared the length of the neuriutas in cultures without treatment (control) (* p <; 0.05; ** p < 0.02; *** p < 0.001 **** p < 0.0005). P2d, which is a peptide fragment of the Ig2 module of NCAM (see Soroka et al., 2002), was used as a positive control to indicate sensitivity of the cells to the treatment. Figure 9 demonstrates the effect of the P3-G peptide on the excrescence of CGN neurites grown as individual neurons in primary culture for 24 hours in the presence of different concentrations of the peptide in the growth medium. The length of the neurites is expressed in arbitrary units (AU). The length of neurites in treated cultures is compared to the length of neurites in cultures under treatment (control). P2d was used as a positive control * p < 0.05, ** p < 0.02; *** p < 0.001 **** p < 0.0005. Figure 10 demonstrates the effect of the P2-EF peptide on the excrescence of CGN neurites grown as individual neurons in primary culture for 24 hours in the presence of different concentrations of the peptide in the growth medium. The length of the neurites is expressed in arbitrary units (AU). The length of the neurites in the treated cultures is compared to the length of the neurites in culture without treatment (control). P2d co or a positive control * p < 0.05, ** p < 0.02; *** p < 0.001 **** p < 0.0005. Figure 11 demonstrates the effects of the Pl-CD peptide on the outgrowth of CGN neurites grown as individual neurons in primary culture for 24 hours in the presence of different concentrations of the peptide in the growth medium and in the co-culture of CGN with genetically modified fibroblasts with (LB?) or without (LV?) expression of? CAM. It can be seen that the peptide does not affect the NCAM-independent neurite excrescence of the CGN in both cultures, but inhibits the CAM-dependent neurite excrescence by interfering with the homophilic adhesion of? CAM in co-cultures of LB cells? and CG ?. The length of the neurites are expressed in arbitrary units (AU). The length of neurites in treated cultures compares the length of neurites in cultures under treatment (control). P2d was used as a positive control *** p < 0.001. Figure 12 demonstrates the effects of peptide P2-A'B on the excitation of CG neurites? cultured as individual neurons in primary culture for 24 hours in the presence of different concentrations of the peptide in the growth medium and in the co-culture of GC? with fibroblasts genetically modified with (LB?) or without (LVN) expression of? CAM. In the figure it can be seen that the peptide does not affect the neuron excrescence independent of? CAM of the CGN in both cultures, and inhibits the NCAM-dependent neurite excrescence by interfering with the homologous adhesion of NCAM in co-cultures of LBN and CGN. The length of the neurites are expressed in arbitrary units (AU). The length of neurites in treated cultures compares the length of neurites in cultures without treatment (control). P2d was used as a positive control *** p < 0.001. Detailed Description of the Invention Molecules with the potential to promote neurite excrescence as well as stimulate survival, regeneration and modulate adhesion in neuronal cells, such as certain endogenous trophic factors and adhesion molecules, eg NCAM, are primary targets. in the search for compounds that facilitate, for example, neuronal regeneration and other forms of neuronal plasticity. To evaluate the potential of the compounds to interfere with cell adhesion, one can investigate the ability to stimulate neurite excrescence, regeneration and survival of neuronal cells, a capacity of the compounds to interact with? CAM. It is an object of the present invention to provide compounds capable of binding to one or more positions in the NCAM molecule. In particular, the positions in the Igl, Ig2 and / or Ig3 modules of? CAM that constitute a homophilic binding site of? CAM described in the present application. NCAM is a multifunctional adhesion molecule. It is understood as a key molecule in different processes associated with neural plasticity during embryonic development, in the adult brain and in association with disease. The involvement of NCAM in different processes that are the basis of neural plasticity is provided by the ability of NCAM to cis- and trans-homophilic interactions and heterophilic interactions with several modular receptors and other cellular and extracellular molecules. The NCAM molecule has multiple overlap and non-overlap binding sites for interaction with these molecules, which are located in different extracellular NCAM modules and in the intracellular domain of NCAM. The present invention relates to a method for modulating the differentiation, adhesion and / or survival of cells presenting NCAM, the method comprising providing a compound capable of interacting with a novel homologous binding site of NCAM composed of ammonia residues of the Igl, Ig2 and Ig3 modules of NCAM. The ammonia residues of the binding site are capable of the following interactions: ammonia residues from the binding site located in the Igl module of an NCAM molecule of the interaction with ammonia residues of the binding site located in the Ig3 module of another , 'the molecule in opposite NCAM, but not with the residues of the binding site located in the Igl or Ig2 modules of this molecule? CAM opposite, - ammonia residues from the binding site located in the Ig2 module of a molecule? interaction with ammonia residues of the binding site located in the Ig2 module of another, the CAM molecule opposite, but not with the residues of the binding site located in the Igl or Ig3 modules of this molecule in opposite CAM, and residues of amino acids from the binding site located in the Ig2 module of a CAM molecule of the interaction with ammonia residues of the binding site located in the Ig3 d module and another, the CAM molecule opposite, but not with the residues of the binding site located in the Ig2 or Igl modules of this molecule? CAM opposite, amino acid residues of the binding site located in the Ig3 module of an NCAM molecule of the interaction with the ammonia residues of the binding site located in the Ig2 module of another, the opposite NCAM molecule, but not with the residues of the binding site located in the Ig3 or Igl modules of this opposite NCAM molecule, ammonia site residues of binding located in the Ig3 module of an NCAM molecule of the interaction with the ammonia residues of the binding site located in the Igl module of another, the opposite NCAM molecule, but not with the residues of the binding site located in the Ig3 modules or Ig2 of this opposite NCAM molecule. According to the invention, a compound, which is - able to i) interact with the Igl module of NCAM, and in this way imitate and / or modulate the interaction between the Igl and Ig3 modules of NCAM, where the modules are of two individual NCAM molecules, and / or ii) interact with the NC3 Ig3 module, and thus mimic and / or modulate the interaction between the Ig3 and Igl modules of? CAM, where the modules are of two individual? CAM molecules, and / or iii) interact with the Ig2 module of NCAM, and in this way mimic the interaction between the Ig2 and Ig3 modules of? CAM, where the modules are of two individual molecules? CAM, and / or iv) interact with the Ig3 module of? CAM, and thus imitate and / or modulate the interaction between the Ig3 and Ig2 modules of? CAM, where the modules are of two molecules? individual CAMs, and / or v) interact with the Ig2 module of NCAM, and thus mimic and / or modulate the interaction between the Ig2 and Ig2 modules of NCAM, where the modules are of two individual NCAM molecules, is a ligand of the homophilic binding site above and is capable of modulating a process assisted by homologous binding of NCAM through the anterior binding site by interacting with this binding site. The term "individual" in relation to two or more molecules / modules / fragments is used to indicate that these two or more molecules / module / fragments are present as separate, unconnected substances. The term "interact" is used herein synonymously with the term "join". The term "ligand" is defined as a compound, which binds to the binding site of the foregoing and mimics the homologous NCAM binding. The term "mimic" is understood as the ability of the ligand to induce / stimulate or inhibit a biological process, which was measured by NCAM through homophilic interaction through the anterior binding site. The ligand can also inhibit interactions that occur naturally, such as by binding to parts of NCAM that are not a part of the binding site, and where the interference is only a spherical interference. The compounds of interaction / binding to the binding site of the invention are favorable for the promotion of neurite excrescence. The compounds of the invention are therefore considered to be good promoters of the regeneration of neuronal connections, and thus of functional recovery after damage, as well as promoters of neuronal function in other conditions where this effect is required. In the present context "differentiation" relates the processes of cell maturation, such as, for example, extension of neurites of neurons that takes place after the last cell division of the neurons has ended. The compounds of the present invention may be able to arrest cell division and initiate the maturation and / or extension of neurites. In the present invention, a compound is considered promising when it is capable of stimulating neurite outgrowth, for example, when it is capable of stimulating the excitation of neurites and cultured cells as compared to control cells, such as improving the excitation of neurites by 50% or more, such as 75%, for example 100% or more. Additionally, in the present context, the text "stimulate / promote survival" is used synonymously with the text "prevent cell death" or "neuro-protection". By stimulating / promoting survival it is possible to prevent diseases or prevent further degeneration of the nervous system of individuals suffering from a neurodegenerative disorder. "Survival" refers to the process, where a cell has been traumatized and under normal conditions, with a high probability will die, if the compound of the invention was not used to prevent the cells from degenerating, and in this way promote or stimulate the survival of the traumatized cell. By the term "modulation" is meant a change such as either stimulation or inhibition. A compound of the invention is capable of modulating processes mediated by homologous NCAM binding. In this way, the compound is capable of stimulation or inhibition of differentiation and / or survival of neural cells. These latter processes may include the activation or inhibition of NCAM signaling. In this way, the compound, which is capable of modulating the above processes dependent on NCAM, is considered by the invention as a compound, which is capable of modulating NCAM signaling. Under the ability of a compound "to modulate NCAM signaling" is meant a capacity of a molecule to modulate the process of initiating the production of second messenger molecules and / or the activation or inhibition of a cascaded intracellular reaction leading to a physiological response of the cell, such as for example an increase in the length of the neurites in response to the binding of the ligand to the homophilic binding site of the invention. The invention also provides a compound capable of "interfering with cell adhesion". This refers to the process wherein the cells attract each other and wherein the present compound is capable of either stimulating or inhibiting this attraction. • The compounds according to the invention also refer to the prevention of neuronal cell death. The cells of the peripheral nerves have to a limited degree a potential to regenerate and re-establish functional connections with their targets after several injuries. However, functional recovery is completely rare and damage to the peripheral nerve cell remains a considerable problem. In the central nervous system, the regeneration potential is even more limited. Therefore, the identification of substances with the capacity to prevent death in neuronal cells in the peripheral and central nervous system is significant and of great commercial value. The compounds of the present invention may be peptides, such as fragments of the peptide portions of the binding site, or peptides comprising the amino acid sequences of the binding site.

In a further embodiment of the invention, the compounds may comprise other chemical entities, such as sugar, cholesterol and fatty acid. Preferably, the chemical entity is linked to the N-terminus or C-terminus of the peptide of the compound. It is an aspect of the present invention that the compounds are capable of binding to the Igl and / or Ig2 and / or Ig3 modules of NCAM at the homophilic binding site of the invention, or at any other site of the NCAM module consisting of of the Igl, Ig2 and Ig3 modules and of mimicking the effect of binding on the homophilic binding site, or of modulating this effect. Without being bound by theory, the present inventors believe that the ligands active to the Igl and / or Ig2 and / or Ig3 modules of NCAM are ligand that bind to the Igl and / or Ig2 and / or Ig3 modules of NCAM and that way they activate a conformational change of the module that results in a signaling cascade when initiated, where the signaling results in a physiological change in the cell, such as influencing cell survival, cell adhesion and / or neurite excrescence . In this manner, a compound according to the invention can be any compound described above that can activate a conformational change of the NCAM Igl module and / or the NCAM Ig2 module and / or the NCAM Ig3 module which results in a change in the signaling cascade of later stages. Modulation Method Thus, it is an object of the present invention to provide a method for modulating the adhesion, differentiation and / or survival of NCAM-presenting cells, by a) providing a candidate compound capable of interacting with an homologous NCAM binding site composed of ammonia residues from the Igl, Ig2 and Ig3 modules of NCAM, by i) interacting with the Igl module of NCAM, and in this way imitate and / or modulate the interaction between the Igl and Ig3 modules of NCAM, where the modules are of two individual NCAM molecules, and / or ii) interact with the NCAM Ig3 module, and thus mimic and / or modulate the interaction between the Ig3 and Igl modules of NCAM, where the modules are of two molecules Individual NCAMs, and / or iii) interact with the NCAM Ig2 module, and thus mimic the interaction between the NCAM Ig2 and Ig3 modules, where the modules are of two individual CAM molecules, and / or iv) interact with the mod Ig3 of? CAM, and in this way mimic and / or modulate the interaction between the Ig3 and Ig2 modules of? CAM, where the modules are of two individual NCAM molecules, and / or v) interact with the IgAM module of NCAM, and thus mimic and / or modulate the interaction between the NCAM Ig2 and Ig2 modules, wherein the modules are of two individual NCAM molecules. b) providing at least one cell presenting? CAM; c) modulating the cellular differentiation and / or survival of at least one cell presenting "CAM" to contact at least one cell presenting "CAM" with the compound, and thus the present invention relates to the cell presenting NCAM , which is i) a cell, which naturally expresses an NCAM molecule on the cell surface, such as for example a neural cell, a muscle cell or a cell of any other tissue, ii) a cancer cell, which expresses a molecule of NCAM on the cell surface; iii) a recombinant cell, which was genetically modified to express a CAM molecule on the cell surface. The cell that has "CAM" of the above can be a cell in vivo, such as a cell in the body of an animal, or it can be a cell grown in vitro. Accordingly, the above method can be used to modulate the differentiation, survival and / or adhesion of cells that exhibit NCAM both in vivo and in vitro. In some embodiments, the method is for in vitro use, and in other embodiments the method is for in vivo use. The method of the foregoing comprises providing a compound capable of interacting with the homophilic binding site of CAM composed of the ammonia residues of the Igl modules., Ig2 and Ig3 of? CAM. In one modality, it can be a compound capable of interacting with the residues of the Igl module of? CAM and in this way mimic and / or modulate the interaction between the Igl and Ig3 modules of? CAM, where the modules are of two molecules? Individual CAM In another modality, this can be a compound capable of interacting with the residues the Ig3 module of? CAM, and in this way mimic and / or modulate the interaction between the Ig3 and Igl modules of? CAM, where the modules are two individual molecules? CAM. In yet another embodiment, the compound is able to interact with the Ig2 module residues, and thus mimic the interaction between the Ig2 and Ig3 modules, where the modules are of two individual CAM molecules. In yet another embodiment, the compound may be able to interact with the Ig3 module residues, and thereby mimic and / or modulate the interaction between the NCAM Ig3 and Ig2 modules, wherein the modules are from two individual NCAM molecules. In yet another embodiment, the compound may be able to interact with the residues of the NCAM Ig2 module, and thereby mimic and / or modulate the interaction between the IgAM and Ig2 modules of NCAM, wherein the modules are of two NCAM molecules individual The above compounds can be represented by a) molecules, which are capable of all the above interactions (i) to (v), or some of the above interactions, such as for example the interaction of (i) and (ii), or (i) and (iii) or any other combination of the interactions of (i) to (v), or b) molecules that are capable of only one selected interaction of any of the interactions (i) to (v). The provision of a compound capable of one or more of the above interactions can be made in one embodiment by using a method for selecting a candidate compound described in the present application. In another embodiment it can be done by using a method for testing a compound described in the application below. All the compounds of (a) and (b) are presumed to be capable of modulating the functions of? CAM, if the execution of the functions by a molecule? CAM comprises one or more interactions (i) to (v) of the above . Under the compound capable of "mimicking" the interaction is meant a compound that acts as a ligand of the homophilic binding site of the foregoing capable of binding to the Igl, Ig2 and Ig3 modules, and thereby replacing the binding to these modules of the Ig3, Ig2 or Igl modules of the other, the opposite, NCAM molecule, respectively, as described above. The imitation is the result according to the invention of stimulating or inhibiting a biological process related to this last union. The present inventors present herewith the model for the homologous binding of NCAM, wherein the Ig and Ig2 modules mediate the dimerization of individual NCAM molecules located on the same cell surface (cis interaction), and where the Ig3 modulus measured the interactions between the individual NCAM molecules expressed on the surface of opposite cells (trans interaction) through the simultaneous binding to the Igl and Ig2 modules. This arrangement results in the formation of a NCAM double zipper adhesion complex. NCAM Sequences A compound of the invention may be a peptide fragment derived from the NCAM sequence, or a variant of the peptide fragment. The peptide fragment may be a fragment of the NCAM sequence identified as the access number of SwissProt NP_113709 (SEQ ID No.:44) or accession number of SwissProt P13591 (SEQ ID No.:45). A preferred peptide fragment can be selected from the amino acid sequences identified below: WFSPNGEKLSPNQ (SEQ ID No .: 1) YKCWTAEDGTQSE (SEQ ID No: 2) TLVADADGFPEP (SEQ ID No: 3) QIRGIKKTD (SEQ ID No .: 4) DVR (SEQ ID No. 5) RGIKKTD (SEQ ID NO: 6) DVRRGIKKTD (SEQ ID NO: 7) KEGED (SEQ ID NO .: 8) IRGIKKTD (SEQ ID No .: 9 KEGDGIRGIKKTD (SEQ ID No .: 10) DKNDE (SEQ ID No .: 11) TVQARNSIVNAT (SEQ ID No .: 12) SIHLKVFAK (SEQ. ID No .: 13) LSNNYLQIR (SEQ ID NO: 14) RFIVLSNNYLQI (SEQ ID No .: 15) KKDVRFIVLSNNYLQI (SEQ ID No .: 16) QEFKEGEDAVIV SEQ ID No: 17 ) KEGEDAVIVCD SEQ. ID. No .: 18) GEISVGESKFFL (SEQ ID No .: 19) KHIFSDDSSELTIRNVDKNDE (SEQ ID No .: 20), AFSPNGEKLSPNQ (SEQ ID No .: 40), AKSWTAEDGTQSE (SEQ ID No .: 41) DVRRGIKKTD (SEQ ID No .: 42) QIRGIKKTD (SEQ ID NO: 43). The sequence of the above amino acids is derived from the rat NCAM sequence having the access number of SwissProt NP_113709 (SEQ ID No .: 40). Another preferred peptide fragment can be selected from fragments or variants of the sequences identified above. The "variant" is to be understood as being any peptide sequence capable of interacting with the Igl, Ig2 and / or Ig3 modules of NCAM and through the interaction induce differentiation, modulate cell adhesion, stimulate regeneration, neuronal plasticity and survival of cells Thus, the fragment or variant is a biologically active compound and can be defined as a compound i) comprising a sequence of ammonia acids capable of being recognized by an antibody, which is also capable of recognizing the predetermined NCAM ammonia sequence, and / or ii) comprising a sequence of ammonia acids that is capable of binding to a receptor portion, which is also capable of binding to the predetermined NCAM ammonia sequence, and / or iii) having a substantially binding affinity. similar to at least one of the Igl, Ig2 or Ig3 modules as the predetermined NCAM amino acid sequence. Thus, according to the invention, a variant such as the functional equivalent of a preferred peptide fragment of the foregoing. A variant of the full-length NCAM protein, such as the NCAM of SEQ. ID. No.: 44 or 45, may be represented by a natural isoform of the protein, such as natural soluble NCAM molecules, shorter or longer NCAM polypeptides generated as a result of alternative splicing, or it may be a recombinant protein containing a NCAM fragment comprising 30-100% of the residues of the full-length protein, or it may be a protein having NCAM homology. The homology between the amino acid sequences can be calculated using well known algorithms such as BLOSUM 30, BLOSUM 40, BLOSUM 45, BLOSUM 50, BLOSUM 55, BLOSUM 60, BLOSUM 62, BLOSUM 65, BLOSUM 70, BLOSUM 75, BLOSUM 80 , BLOSUM 85 or BLOSUM 90. Homologs are to be considered within the scope of the present invention when they are at least about 40 percent homologous with the NCAM of SEQ. ID. No.: 44 or 45, such as at least about 50 percent homologous, for example at least about 60 percent homologous, such as at least about 70 percent homologous, for example at least about 75 percent homologous, such as less than about 80 homologous, for example at least about 85 percent homologous, such as at least about 90 homologous, e.g. at least 92 homologous, such as at least 94 homologous, e.g. at least 95 percent homologous, such as at least 96 percent homologous, for example at least 97 percent homologous, such as at least 98 percent homologous, for example at least 99 percent homologous. According to one embodiment of the invention, the percentages of homology are deferred to the identity percentages. The variant of NCAM is according to the invention a functional variant, such as a variant that maintains a capacity of the full-length protein to homophilic binding through the binding site of the invention and which performs the functions assisted by this binding . The binding affinity of the compound according to the invention preferably has a binding affinity (Kd value) to the NCAM modules in the range of 10"3 to 10" M, such as preferably in the range of 10"4 a "8 M. According to the present invention, the binding affinity is determined by one of the following tests of the surface plasmon resonance analysis or nuclear magnetic resonance spectroscopy In one embodiment, the variants can be understood as exhibiting sequences of amino acids that differ gradually from the preferred predetermined sequence, such as the number and range of insertions, deletions and substitutions including increment in conservative substitutions.This difference is measured as a reduction in homology between the predetermined sequence and the variant. of peptide sequences "means that the peptides can be modified, for example by substitution of one or more of the ammonia residues, Both L-ammoniacs and D-ammonium acids can be used, Another modification can comprise derivatives such as esters, sugars, etc. The examples are methyl and acetyl esters. or repetitive sequences or binding to various carriers are well known in the art for example, lysine structures, such as lysine dendrimers having 4 peptides, 8 peptides, 16 peptides or 32 peptides. Other carriers may be protein portions, such as bovine serum albumin (BSA), or lipophilic dendrimers, or micelle-type carriers formed by lipophilic derivatives, or starburst carbon chain polymer conjugates (star type), or presenting the ligand (LPA) based on diethylaminomethane derivatives. The variants of the peptide fragments according to the invention may comprise, within the same variant, or fragments thereof, or between different variants or fragments thereof, at least one substitution, such as a plurality of independently introduced substitutions. each. The variants of the complex, or fragments thereof, may thus comprise conservative substitutions independently of one another, wherein at least one glycine (Gly) of the variant or fragments thereof is substituted with an amino acid selected from the group of amino acids consisting of of Ala, Val, Leu e lie, and independently thereof, variants, or fragments thereof, wherein at least one alanine (Ala) of the variants, or fragments thereof, is substituted with an amino acid selected from the group of amino acids consisting of Gly, Val, Leu e lie, and independently thereof, variants, or fragments thereof, wherein at least one valine (Val) of the variant, or fragments thereof, is substituted with a amino acids selected from the group of amino acids consisting of Gly Val, Leu e lie, and independently thereof, variants, or fragments thereof, wherein at least one leucine (Leu) of the variant, or fragments thereof, is substituted with an ammonia selected from the group of ammoniacs consisting of Gly, Ala, Val e lie, and independently thereof, variants, or fragments thereof, wherein at least one isoleucine (lie) of the variants, or fragments thereof, are substituted with an ammonia selected from the group of amino acids consisting of Gly, Ala, Val, and Leu, and independently thereof, variants, or fragments thereof, wherein at least one Aspartic acid (Asp) of the variant, or fragments thereof, is substituted with an amino acid selected from the group of ammonia acids consisting of Glu, Asn, and Gln and independently thereof, variants, or fragments thereof, wherein at least one aspargin (Asn) of the variants, or fragments thereof, is substituted with an amino acid selected from the group of ammoniacs consisting of Asp, Glu and Gln, and independently thereof, variants, or fragments thereof, wherein at least one glutamine (Gln) of the variants, or fragments thereof, is substituted with an amino acid selected from the group of ammonia acids consisting of Asp, Glu and Asn and wherein at least one phenylalanine (Phe) of the variants, or fragments thereof, is substituted with a selected amino acid of the ammonia group consisting of Tyr, Trp, His, Pro and preferably selected from the group of ammoniacs consisting of Tyr and Trp, and independently thereof, variants, or fragments thereof, wherein at least one tyrosine (Tyr) of the variants, or fragments thereof, is substituted with an ammonia selected from the group of amino acids consisting of Phe, Trp, His, Pro, and preferably an amino acids selected from the group of amino acids consisting of Phe and Trp, and independently thereof, variants, or fragments thereof, wherein at least one arginine (Arg) of the fragment is substituted with an amino acid selected from the ammonium group. acids consisting of Lys and His, and independently thereof, variants or fragments thereof, wherein at least one lysine (Lys) of the variants, or fragments thereof, is substituted with an amino acids selected from the group of ammonia acids which consists of Arg and His, and independently thereof, variants, or fragments thereof and wherein at least one proline (Pro) of the variants, or fragments thereof, is substituted with an amino acid selected from the group of ammonia acids which consists of Phe, Tyr, Trp and His, and independently thereof, variants, or fragments thereof, wherein at least one cysteine (Cys) of the variants, or fragments thereof, is substituted with an amino acid selected from the group of amino acids that consists of Asp, Glu, Lys, Arg, His, Asn, Gln, Ser, Thr and Tyr. Thus, it follows from the foregoing that the same functional equivalent of a peptide fragment, or fragment of the functional equivalent, may comprise more than one conservative substitution of amino acids from more than one group of conservative amino acids as defined hereinbefore. The term "preservative substitution of amino acids" is used in a manner comparable herein with the term "homologous substitution of ammonium acids". The groups of preservative ammonia acids are the following: P, A, G, S, T (neutral, weakly hydrophobic), Q, N, E, D, B, Z (hydrophilic, acidic amine), H, K, R (hydrophilic) , basic), F, Y, W (hydrophobic, aromatic), L, I, V, M (hydrophobic) C (crosslinking) Conservative substitutions can be introduced at any position of a peptide for the particular preferred of the invention or fragment of it. However, it may also be desirable to introduce non-conservative substitutions, particularly, enunciatively and without limitation, a non-conservative substitution in any of one or more positions. A non-conservative substitution leading to the formation of a functionally equivalent fragment of the peptide of the invention will differ for example substantially in polarity, for example a residue with a non-polar side chain (Ala, Leu, Pro, Trp, Val, Lie, Leu Phe or Met) substituted by a residue with a polar side chain such as Gly, Ser, Thr, Cys, Tyr, Asn or Gln or a charged ammonia such as Asp, Glu, Arg or Lys or by substituting a charged or polar by a non-polar residue; and / or ii) differ substantially in their effect on orientation of the peptide structure such as substitution of or by Pro or Gly for another residue; and / or iii) differ substantially in electrical charge, for example substitution of a negatively charged residue such as Glu or Asp by a positively charged residue such as Lys, His or Arg (and vice versa); and / or iv) differ substantially in the steric mass, for example substitution of a mass residue such as His, Trp, Phe or Tyr by one having a minor side chain, for example, Ala, Gly or Ser (and vice versa). The substitution of ammonia acids can be made in a mode based on their hydrophobicity and hydrophilicity values and the relative similarity of amino acid side chain substituents, including charge, size and the like. Substitutions of example ammonia which take several of the above characteristics into consideration are well known to the person skilled in the art and include; arginine and lysine; glutamate and aspartate; serine and threonine; glutamine and asparagine; and valine, leucine and isoleucine.

The addition or suppression of an amino acid may be an addition or deletion of 2 to preferably 10 amino acids, such as 2 to 8 amino acids, for example 2 to 6 amino acids, such as 2 to 4 amino acids. However, additions of more than 10 amino acids, such as additions of 2 to 10 amino acids, are also encompassed within the present invention. In multimeric forms, additions / deletions can be made individually in each monomer of the multimer. The invention also relates to non-peptide variants of the compounds described herein. In particular, these variants should be understood to be compounds that are constituted to or otherwise interact with the Igl, Ig2 or Ig3 modules of NCAM and thus stimulate the signaling of Igl, Ig2, operation3 and / or modulate proliferation and / or induce differentiation and / or stimulate regeneration, neuronal plasticity and / or survival of cells that present an NCAM receptor. Functional Equivalent A functional equivalent can be obtained by substitution of an amino acid in the sequence, which has a functional activity according to the invention. Functionally similar in the present context refers to dominant characteristics of side chains such as hydrophobic, basic, neutral or acid, or in the presence or absence of steric mass. Accordingly, in one embodiment of the invention, the degree of identity between i) a given functional equivalent capable of the effect and ii) a preferred predetermined fragment, is not a primary measure of the fragment as a functional variant or equivalent of a predetermined peptide fragment preferred according to the present invention. Fragments that share at least some homology with a preferred predetermined fragment of at least 3 amino acids, more preferably at least 5 amino acids, are to be considered as falling within the scope of the present invention when they are at least about 25 percent. homologues with the preferred predetermined NCAM peptide, or fragment thereof, such as at least about 30 percent homologous, for example at least about 40 percent homologous, such as at least about 50 percent homologous, for example at least about 55 homologous percent, such as at least about 60 percent homologous, for example at least about 65 percent homologous, such as at least about 70 percent homologous, such as at least about 75 percent homologous, for example at least about 80 percent homologs, such as at least about 85 percent homologo you. Sequence identity can be measured using sequence analysis software (for example, the sequence analysis program package of the Genetics Computer Group, University of Wisconsin Biotechnology Center, 1710 University Avenue, Madison, Wl 53705), with the parameters by default as specified therein. Where nothing is specified it is to be understood that the C-terminal amino acid of a polypeptide to the invention exists as the free carboxylic acid, this can also be specified, - "OH". However, the C-terminal amino acid of a compound of the invention may be the amidated derivative, which is indicated as "-NH2" -. Where also nothing is declared the N-terminal amino acids and a polypeptide comprises a free amino group, this can also be specified as "H-". Where nothing is specified either, an amino acid of any amino acid may be selected, whether present naturally or not, such as alpha-amino acids, beta-amino acids, and / or gamma-amino acids. Accordingly, the group includes, without limitation, Ala, Val, Leu, Lie, Pro, Phe, Trp, Met, Gly, Ser, Thr, Cys, Tyr, Asn, Gln, Asp, Glu, Lys, Arg. , His, Aib, Nal, Sar, Orn, lysine analogs DAP and DAPA, 4Hyp. Test methods According to the present invention, compounds capable of modulating the interaction between two individual CAM molecules through the homophilic binding site composed of the Igl, Ig2 and Ig3 modules of the NCAM molecules can be identified, by testing their ability to i) interact with the Igl module. NCAM, and in this way imitate and / or modulate the interaction between the Igl and Ig3 modules of NCAM, where the modules are of two individual fragments of (b) that interact with each other, and / or ii) interact with the Ig3 module of NCAM, and thus mimic and / or modulate the interaction between the Ig3 and Igl modules of NCAM, where the modules are of the two individual fragments of (b) that interact with each other, and / or iii) interact with the NCAM Ig2 module, and in this way mimic the interaction between the Ig2 and Ig3 modules of? CAM, where the modules are of the two individual fragments of (b) that interact with each other, and / or iv) interact with the module NCAM Ig3, and thus mimic and / or modu the interaction between the Ig3 and Ig2 modules of? CAM, where the modules are of the two individual fragments of (b) that interact with each other, and / or v) interact with the Ig2 module of? CAM, and thus mimic and / or modulating the interaction between the Ig2 and Ig2 modules of? CAM, wherein the modules are of the two individual fragments of (b) that interact with each other. The method according to the invention comprises the steps of: a) providing a compound; b) providing at least one individual fragment of an NCAM molecule, wherein the fragment comprises a sequence of consecutive residues of ammonia acids corresponding to the sequence of the Igl-2-3 NCAM module comprising residues 1 to 289 of the sequence exposed in SEQ. ID. Do not . : 40 or fragments of this sequence; c) contacting the compound of (a) with the individual NCAM fragment from (b), and d) testing whether the compound is capable of interacting with the Igl module of NCAM, and thus mimicking and / or modulating the interaction between the Igl and Ig3 modules of? CAM, where the modules are of the two individual fragments of (b) that interact with each other, and / or - interact with the Ig3 module of? CAM, and thus mimic and / or modulate the interaction between the Ig3 and Igl modules of? CAM, where the modules are of the two individual fragments of (b) that interact with each other, and / or - interact with the Ig2 module of? CAM, and thus mimic the interaction between the Ig2 and Ig3 modules of? CAM, where the modules are of the two individual fragments of (b) that interact with each other, and / or - interact with the NC3 Ig3 module, and thus mimic and / or modulate the interaction between the Ig3 and Ig2 modules of NCAM, where the modules are of the two individual fragments of (b) that interact with each other, and / or - interact with the NCAM Ig2 module, and thus mimic and / or modulate the interaction between the Ig2 modules - and NCAM Ig2, where the modules are of the two individual fragments of (b) that interact with each other d) provides a candidate capable of any of the above interactions. In one embodiment of the invention, the individual? CAM fragment is represented by the Igl-2-3 module of? CAM comprising a consecutive sequence of at least 289 amino acids of the? CAM sequence. In a more preferred embodiment, the sequence comprises aa 1 to 289 of? CAM, where? CAM is? Rat CAM having the access number? CBI? P_113709 identified as SEQ. ID. Do not . : 40 of the present application. By the "Igl-2-3 module of NCAM" in the present context is meant a contiguous sequence of amino acids as described above consisting of the Igl, Ig2 and Ig3 sequences, and the linking sequences connecting the modules in The following order:? -Termino < Igl-ligador-Ig2 -ligador-Ig3 > C-term.The Igl-2-3 module can be a recombinant molecule consisting of the Igl, Ig2, and Ig3 modules or it can be a recombinant fusion protein containing the Igl, Ig2 and Ig3 modules and a fusion partner, or it can be a fragment of a full length NCAM molecule obtained by any method known in the art In accordance with the previous invention, the Igl module -2-3 of the above method is in solution In one embodiment, the solution is an aqueous solution In a preferred embodiment, the solution is phosphate buffered saline (PBS) or a TRIS-HCl buffer, pH 7.4. of the contact of a compound with The individual NCAM fragment from step (c) is preferably presented in solution of the Igl-2-3 module. Testing whether the compound is capable of the above interactions can be done by any method available in the art currently used for the detection of protein interactions. For example, NMR spectroscopy can be selected as an appropriate method, or it can be done by using Plasmon resonance analysis. According to the invention, evaluation by NMR is preferred. A compound capable of the above interactions is identified by the above method and is designated according to the invention as a candidate compound. The candidate compound can be further tested for its ability to modulate the interaction between at least two individual NCAM modules, such as i) the Igl module and the Ig3 module, and / or ii) the Ig2 module and the Ig3 module, and / or iii) the Ig2 module and the Ig2 module.

This latter test can be done for example by using gel filtration of the Igl-2-3 module in solution in the presence of the selected candidate compound. It can be done by using gel filtration of a mixture of Igl and Ig3 modules, or a mixture of the individual Ig2 and Ig3 modules, or a mixture of two individual NCAM fragments, each of which consists of the contiguous sequence of the Igl and Ig3 modules, or the fragments consisting of the Ig2 and Ig3 modules . Gel filtration chromatography is one of the most commonly used laboratory techniques and the expert can easily perform this test. According to the present invention, the candidate compound can be any molecule capable of modulating the interactions of NCAM Igl, Ig2 and Ig3 modules of the above. This compound can be selected for example from the group comprising libraries of combination of peptides, lipids, carbohydrates or other organic molecules, or copolymers of amino acids with other organic compounds. In a preferred embodiment, the candidate compound of the invention is a peptide. } The purpose of the above test method is the identification and selection of the compounds of interest (candidate compounds) capable of interacting with the Igl-2-3 module of NCAM in the binding site of the invention and thus modulating the differentiation, adhesion and / or cell survival dependent on NCAM. Crystal According to the invention, the identification of a candidate compound can comprise the use of a crystal protein comprising either the individual Igl, Ig2 and Ig3 modules or a combination of these modules. A crystalline protein of the NCAM Igl-2-3 module consisting of the amino acid sequence corresponding to the ammonia residues 1-289 of rat NCAM (accession number of SwissProt NP_113709) (SEQ ID No. 40) ) is made by the authors of the present invention to determine the structure of the homophilic binding site of? CAM and the computer generated 3D structure of the module is proposed for the detection in silicon of compounds capable of detecting the identified binding site Homophile In a preferred embodiment, the crystal protein of the invention is a crystal of a polypeptide comprising the Igl-2-3 module of? CAM comprising a homophilic binding site of? CAM. The crystal may comprise more than one polypeptide, for example, two polypeptides. In a preferred embodiment, the crystal comprises Igl, Ig2 and Ig3 modules of? CAM co-linked in a fragment by interconnecting amino acid sequences, fragment referred to herein as the "Igl-2-3 fragment".

Therefore, it is preferred that the crystal diffract X-rays for determination of atomic coordinates at a resolution of at least 4 Á, preferably at least 3 Á, more preferably at least 2.8 Á, even more preferably at minus 2.5 Á, more preferably at least 2.0 Á. In a more preferred embodiment of the invention, the crystal comprises atoms arranged in a spatial relationship represented by the structure coordinates of Table 2 shown in Figure 2, or by the coordinates having a mean square root deviation from no more than 2.5A, preferably not more than 2.25A, more preferably not more than 2.0A, even more preferably not more than 1.75A, still more preferably not more than 1.5A, for example not more than 1.25A A, such as no more than 1.0 Á. Preferably, the coordinates have an average square root deviation from, not more than 2.5 A, preferably not more than 2.25 A, more preferably not more than 2.0 A, more preferably not more than 1.75 A, even more preferably not more than 1.5 Á, for example no more than 1.25 Á, such as no more than 1.0 Á. Preferably, the crystal comprises or consists more preferably of the structure as it is deposited to the PDB with id 1QZ1. The crystal may comprise more than one polypeptide of the NCAM Igl-2-3 fragment per asymmetric unit, in a preferred embodiment of the invention, the crystal comprises polypeptides of the NCAM Igl-2-3 module per asymmetric unit. It is preferred that the crystal have unit cell dimensions in the range of a = 50 to 52, preferably 50.5 to 51.0, more preferably about 51.5; b = 107.5 to 109.5, preferably from 108 to 109, and more preferably around 108.5; c = 146 to 151, preferably 148 to 150, more preferably about 149.0; a = 85.5 to 95.5, preferably from 88 to 92, more preferably close to 90; ß = 85.5 to 95.5, preferably 88 to 92, more preferably about 90; ? = 85.5 to 95.5, preferably 88 to 92, more preferably around 90. More preferably, the crystal has the following characteristics: Space group: 12x2x21 with 1 molecule per asymmetric unit, unit cell dimensions a = 51.5 b = 108.5 c = 149.0 A alpha = 90 ° beta = 90 ° gamma = 90 °. Preparation of crystals After several unsuccessful attempts, the appropriate conditions were identified to prepare crystals of a polypeptide corresponding to the Igl-2-3 module of NCAM.

Therefore, it is also an aspect of the present invention to provide a crystal comprising a polypeptide comprising at least 289 consecutive amino acid residues corresponding to residues 1-289 of ammonia rat NCAM (access number of? CBI? P__113709) (SEQ ID: 40), these consecutive amino acids correspond to the Igl-2 ~ 3 fragment of? CAM of rat using a method for preparing a crystal, wherein the method comprises the steps of: i) providing the polypeptide, - ii) growing crystals under conditions wherein the polypeptide is incubated in a buffer comprising in the range of 14 to 17% polyethylene glycol 4000 (PEG4k), in the range of 0.150 M to 0.5 M sulfate salt of Li wherein the buffer has a pH in the range of 4.8-5.8; iii) prepare the crystals in this way. In one embodiment of the invention, co-crystals of the polypeptides and a compound capable of interacting with the polypeptide are prepared. This compound may have been identified by any of the methods summarized hereunder. Therefore, the compound can be in one aspect of the invention a modulator, such as a homophilic interaction modulator of? CAM mediated by the Igl-2-3 module of? CAM. Co-crystals are useful for designing optimized compounds, with improved binding properties. In particular, co-crystals can be useful to design better, inhibitors of homophilic interaction mediated by the Igl-2-3 module of NCAM or stabilizers of this interaction. The buffer preferably comprises in the range of 5 to 25% polyethylene glycol, more preferably in the range of 10 to 20%, still more preferably in the range of 12 to 18%, still more preferably the range from 14 to 16%, more preferably about 15% polyethylene glycol. The polyethylene glycol (PEG) can be any suitable PEG for example a PEG selected from the group consisting of PEG 4000, PEG 6000 and PEG 8000, preferably polyethylene glycol is PEG 4000. The buffer preferably comprises a salt in the range of 0.15 M to 0.5 M, more preferably in the range of 0.2 to 0.5 M, still more preferably in the range of 0.3 to 0.5 M, even more preferably in the range of 0.4 to 0.5 M, more preferably preferably a salt of about 0.45 M. The salt can be any useful salt, preferably the salt is Li sulfate (Li2S0). The buffer preferably has a pH in the range of 4.0 to 8.5, more preferably in the range of 4.5 to 7.5, still more preferably in the range of 5.0 to 6.5, still more preferably in the range of 5.0 to 5.2. The shock absorber can be any useful shock absorber, preferably the Na-acetate buffer. Incubation should be performed at a suitable temperature, preferably at a temperature in the range of 5 to 25 ° C, more preferably in the range of 10 to 25 ° C, even more preferably in the range of 15 to 25 ° C. 25 ° C, still more preferably in the range of 17 to 21 ° C, still more preferably around 18 ° C. The crystals can be cultivated by any suitable method, for example by the hanging drop method. Determination of structure The structure can be determined by any method known to the person skilled in the art, for example using X-ray diffraction. Once a structure has been identified, the structure can be refined using an appropriate computer program. In one embodiment of the invention, a molecular replacement technique can be used. These techniques comprise that the structure is determined by obtaining X-ray diffraction data for crystals of the complex polypeptide for which it is desired to determine the three-dimensional structure. Then, the three-dimensional structure of that complex polypeptide is determined by analyzing the X-ray diffraction data using molecular replacement techniques with reference to known structural coordinates of a structurally similar protein. In the case of polypeptide comprising the Igl-2 NCAM modules, structural coordinates of the modules can be used. As described in U.S. Patent No. 5,353,236, for example, molecular replacement uses a molecule having a structure known as a starting point for modeling the structure of an unknown crystalline sample. This technique is based on the principle that two molecules, which have similar structures, orientations and similar positions in the unit cell, are diffracted in a similar way. Molecular replacement comprises placing the known structure in the unit cell in the same location and orientation as the unknown structure. Once placed, the atoms of the known structure in the unit cell are used to calculate the structure factors that will result - from a hypothetical diffraction experiment. This includes the rotation of the known structure in the six dimensions (three angular dimensions and three spatial dimensions) until the alignment of the known structure with the experimental data is achieved. This approximate structure can be finely adjusted to produce a more accurate and often higher resolution structure using various refining techniques. For example, the resulting model for the structure defined by the experimental data can be subjected to rigid body refining in which the model is subjected to additional limited rotation in the six dimensions producing position shifts of below about 5%. The refined model can then be further refined using other known methods of refining. Another method for determining the three-dimensional structure of a polypeptide corresponding to the Ig 1-2-3 module of NCAM, or a complex of this polypeptide with an interacting compound, is homology modeling techniques. Homology modeling comprises constructing a model of an unknown structure using structural coordinates of one or more related proteins, domains and / or protein sub-domains. Homology modeling can be carried out by adjusting common or homologous portions of the protein or peptide whose three-dimensional structure will be solved to the three-dimensional structure of homologous structural elements. Homology modeling can include re-building part or all of the three-dimensional structure with replacement of amino acids (or other components) by those of the related structure to be solved. In example 2 an example of structure determination is summarized. The structural coordinates of a crystalline polypeptide of this invention can be stored in a machine readable form or a machine readable storage medium, for example, a computer disk drive, diskette, DAT tape, CD-ROM, etc. , for display as a three-dimensional form or for other uses that comprise computer-aided manipulation of, or computation based on, the structural coordinates or the three-dimensional structures they define. For example, the data defining the three-dimensional structure of a polypeptide corresponding to the Ig 1-2-3 module of NCAM can be stored in a machine-readable storage medium and can be displayed as a three-dimensional graphic representation of the structure of protein, typically using a computer capable of reading the data from the storage medium and programmed with instructions to create the representation of this data. This invention thus encompasses a machine, such as a computer, having a memory containing data representing the structural coordinates of a crystalline composition of this invention, for example, the coordinates set forth in Table 2 (Figure 2), together with additional optional data and instructions to manipulate this data. These data can be used for a variety of purposes, such as clarifying other related structures and drug discovery. A first set of this machine-readable data can be combined with a second set of machine-readable data using a programmed machine with instructions for using the first data set and the second data set to determine at least a portion of the coordinates that correspond to the second set of machine readable data. For example, the first data set may comprise a Fourier transform of at least a portion of the coordinates for the complex set forth in Table 2 (Figure 2), while the second data set may comprise X-ray diffraction data. of a molecule or molecular complex. More specifically, one of the objects of this invention is to provide three-dimensional structural information of co-complexes comprising the homophilic binding site of the NCAM Ig 1-2-3 module. For this purpose, the use of structural coordinates of a crystalline composition of this invention is provided, or portions thereof, to solve, for example by molecular replacement or by homology modeling techniques, the three-dimensional structure of a crystalline form of another similar cell adhesion molecule (CAM), for example another CAM comprising the Ig modules capable of the homophilic interaction or the complex of the interacting compound: polypeptide.

For example, molecular replacement can be used to exploit a set of coordinates as set forth in Table 2 (Figure 2) to determine the structure of a crystalline co-complex of a polypeptide corresponding to the Ig 1-2-3 module of NCAM comprising a homophilic binding site and an interacting compound. Uses of the structures A 3D representation of the polypeptides described in the present invention can be useful for various purposes, for example to determine the structure of proteins and similar polypeptides, (see also hereinabove) or to design compounds capable of interacting with the polypeptides. For example, the three-dimensional structure defined by the machine-readable data for the polypeptides of the NCAM Ig 1-2-3 module can be evaluated by computation for its ability to associate with various chemical entities or test compounds. The term "chemical entity", as used herein, refers to chemical compounds, complexes of at least two chemical compounds, or fragments of these compounds or complexes. For example, a first set of machine-readable data defining the 3D structure of the polypeptide corresponding to the NC 1-2-3 NCAM module or complex thereof, is combined with a second set of machine-readable data defining the structure of a chemical entity or test compound of interest using a programmed machine with instructions for evaluating the ability of the chemical entity or compound to associate with the NC 1-2-3 NCAM module or complex thereof and / or the location and / or orientation of this association. These methods provide compression of the location, orientation and energy of association of protein surfaces with these chemical entities. The three-dimensional structure defined by the data can be displayed in a graphic format that allows visual inspection of the structure, as well as visual inspection of the association of the components of the polypeptide with an interacting compound. Alternatively, more quantitative or computational methods may be used. For example, the method of this invention for evaluating the ability of a chemical entity to associate with any of the molecules or molecular complexes set forth herein comprises the steps of: (a) cooling counting means to perform an adjustment operation between the chemical entity and a binding site or other surface feature of the molecule or molecular complex; and (b) analyzing the results of the adjustment operation to quantify the association between the chemical entity and the binding site. The invention further provides the use of the structural coordinates of a crystalline composition of this invention, or portions thereof, to identify reactive amino acids, such as cysteine residues, within the three-dimensional structure, preferably within or adjacent to a union site; to generate and visualize a molecular surface, such as a surface accessible to water or a surface comprising the van der Waals surface of space filling of all atoms; to calculate and visualize the size and shape of the surface characteristics of the protein or complex, for example, substrate binding sites; for locating potential H-linkers and acceptors within the three-dimensional structure, preferably within or adjacent to a ligand-binding site; to calculate regions of hydrophobicity and hydrophilicity within the three-dimensional structure, preferably within or adjacent to a ligand-binding site; and for calculating and visualizing regions on or adjacent to the protein surface of favorable interaction energies with respect to selected functional groups of interest (eg, amino, hydroxyl, carboxyl, methylene, alkyl, alkenyl, aromatic carbon, aromatic rings, heteroaromatic rings , etc.), the above approaches can be used to characterize the polypeptide corresponding to the Ig 1-2-3 NCAM module and its interactions with portions of potential interacting compounds to design or select compounds capable of specific covalent binding to reactive ammonia. (eg, cysteine), and to design or select compounds of complementarity characteristics (eg, size, shape, charge, hydrophobicity / hydrophilicity, ability to participate in hydrogen bonding, etc.), for surface features of the protein, a set of which can be preselected. Using the structural coordinates, one can also predict or calculate the orientation, binding constants or relative affinity of a given ligand to the protein in the complex wrapped state, and use this information to design or select compounds of improved affinity. In these cases, the structural coordinates of the NCAM Ig 1-2-3 polypeptide module, or a portion or complex thereof, are entered in machine readable form in a programmed machine with instructions to carry out the desired operation and that contains any additional data necessary, for example, data defining structural and / or functional characteristics of a potential interacting compound or portion thereof, which defines molecular characteristics of various amino acids, etc. The method of this invention provides selection of a database of chemical structures of a composite binding layers to the Igl-2-3 module of NCAM. The method starts with structural coordinates of a crystalline composition of the invention, for example, coordinates defining the three-dimensional structure of the Ig 1-2-3 NCAM module or a portion thereof or a complex thereof. The points associated with the three-dimensional structure are characterized with respect to the favorable capacity of interactions with one or more functional groups. A database of chemical structures is then searched for candidate compounds that contain one or more functional groups placed for favorable interaction with the protein based on the above characterization. In this way, compounds that have structures that better adjust to points of favorable interaction with the three-dimensional structure are identified. It is often preferred, although not required, that this search be carried out with the help of a computer. In that case, a first set of machine-readable data defining the 3D structure of a polypeptide corresponding to the Ig 1-2-3 module of NCAM, or a polypeptide / interacting compound portion or complex thereof, is combined with a second set of machine readable data defining one or more functional portions or groups of interest, using a programmed machine with instructions to identify preferred locations for interaction favorable between the functional groups and polypeptide atoms. A third data set, i.e., data defining the favorable interaction locations between the polypeptide and functional groups is generated in this way. This third set of data is then combined with a fourth set of data that define the 3D structures of one or more chemical entities using a programmed machine with instructions to identify chemical entities that contain functional groups placed to better fit the locations of their favorable interactions. respective with the polypeptide. Compounds having structures selected or designed by any of the above means can be tested for their ability to bind to the Ig 1-2-3 module of NCAM. In a preferred embodiment of the invention, the compound is preferably modulator of the homologous interaction of NCAM mediated by the fragment of Ig 1-2-3. For example, a compound capable of interacting with the homologous binding site of Ig 1-2-3 may be a good inhibitor of the homophilic binding of NCAM and function of NCAM that requires that binding. Therefore, compounds having structures selected or designed by any of the above means can be tested for their ability to modulate NCAM activity, such as mediation of cell differentiation and / or survival of NCAM-presenting cells. As experts in this technique it will be appreciated that, various computational analyzes may be used to determine the degree of similarity between the three-dimensional structure of a given polypeptide (or a portion or complex thereof) of a polypeptide corresponding to the Ig 1-2 module. -3 of NCAM or complex thereof as described herein. These analyzes can be carried out with commercially available computer program applications such as QUANTA's Molecular Similarity application (Molecular Simulations Inc., Waltham, Mass.) Version 3.3, and as described in the accompanying User's Guide, Volume 3 , pages 134-135. The Molecular Similarity application allows comparisons between different structures, different conformations of the same structure, and different parts of the same structure. The procedure used in Similarity Molecules to compare structures is divided into four steps: (1) load the structures to be compared; (2) define the atomic equivalences in these structures; (3) perform an adjustment operation; and (4) analyze the results. Each structure is identified by a name. A structure is identified as the objective (that is, the fixed structure); all remaining structures are work structures (ie structures in motion). Since the atomic equivalence within QUANTA is defined by the user input, for the purpose of this invention, equivalent atoms are defined as atoms of the protein structure (?, Ca, C and 0) for all residues conserved between the two structures that are compared and consider only rigid adjustment operations. When a rigid adjustment method is used, the work structure is moved and rotated to obtain an optimal fit within the target structure. The adjustment operation uses a least-squares adjustment algorithm that computes the optimal translation and rotation to be applied to the motion structure, such that the root-mean-square difference of the fit over the specified pairs of the equivalent atom is an absolute minimum. . This number, given in angstroms, is reported by QUA? TA. For the purpose of this invention, any set of structural coordinates of a peptide corresponding to the Ig 1-2-3 modulus of? CAM or molar complex thereof having a root mean square deviation of atoms of conserved residue structure (? , Ca, C, 0) of less than 1.5 Á when overlapping using atoms of structure, in the relevant structural coordinates of a protein or complex of this invention, for example the coordinates listed in Table 2 (Figure 2), are considered identical Most preferably, the root mean square deviation is less than 1.0 Á. Most preferably, the mean square root deviation is less than 0.5 Á. The term "mean square root deviation" means the square root of the arithmetic mean of the squares of the deviations from the mean. It is a way to express the deviation or variation of a trend or object. For the purposes of this invention, the "mean square root deviation" defines the variation in the structure of a protein of the structure of a protein of this invention, such as a homophilic binding site of the Ig 1-2-3 module of NCAM as defined by the structural coordinates of Table 2 (Figure 2) and described herein. The term "least squares" refers to a method based on the principle that the best estimate of a value is one in which the sum of the squares of the deviations of the observed values is a minimum. In order to use the structural coordinates generated for a crystalline substance of this invention, for example, the structural coordinates set forth in Table 2 (Figure 2), it is often necessary or desirable to display them as, or convert them to, a three-dimensional shape, or manipulate them. else. Typically this is achieved by the use of a commercially available computer program such as a program that is capable of generating three-dimensional graphic representations of moles or portions thereof of a set of structural coordinates. By way of illustration, a non-exclusive list of computer programs for viewing or otherwise manipulating protein structures includes the following: Midas (Univ. Of California, San Francisco), Midas Plus (Univ. Of Cal, San Francisco), MOIL (University of Illinois) Yummie (Yale University) Sybyl (Tripos, Inc.) Insight / Discover (Biosym Technologies) MacroModel (Columbia University) Quanta (Molar Similations, Inc.) Cerius (Molar Simulations, Inc.) Alchemy (Tripos Inc .) LabVision (Tripos Inc.) Rasmol (Glaxo Research and Development) Ribbon (University of Alabama) NAOMI (Oxford University) Explorer Eyechem (Silicon Graphics, Inc.) Univision (Cray Research) Molscript (Uppsala University) Chem-3D (Cambridge Scientific) Chain (Baylor College of Medicine) 0 (Uppsala University) GRASP (Columbia University) X-Plor (Molar Simulations, Inc.; Yale Univ.) Spartan (Wavefunction, Inc.) Catalyst (Molecular Simulations, Inc.) Molcadd (Tripos, Inc.) 'VMD (Univ. Of Illinois / Beckman Institute) Sculpt (Interactive Simulations, Inc.) Procheck (Brokhaven Nat' 1 Laboratory) DGEOM (QCPE) RE_VIEW (Brunel University) Modeller (Birbeck Col., Univ. Of london) Xmol (Minnesota Supercomputing Center) Protein Expert (Cambridge Scientific) HyperChem (Hypercube) MD Dispay (University of Washington) PKB (Nat'l Center for Biotech, Info., NIH) Che X (Chemical Desing, Ltd.) Cameleon (Oxford Molecular, Inc.) Iditis (Oxford Molecular, Inc.) For the storage, transfer and use with these structural coordinate programs for a substance of the invention, a machine-readable storage medium is provided which comprises a data storage material encoded with machine readable data which, when a programmed machine is used with instructions for using this data, for example u A computer loaded with one or more programs of the class identified above is capable of displaying a three-dimensional graphic representation of any of the molecules or molecular complexes described herein. The machine-readable storage medium comprising a data storage material includes conventional computer disk drives, floppy disks, DAT tape, CD-ROM, and other magnificent media, magneto-optical, optical, flóptico and others that can be adapt for use with a computer. Even more preferred is a machine-readable loss of data storage that is capable of displaying a three-dimensional graphic representation of a molecule or molecule complex that is defined by the structural coordinates of the NCAM Ig 1-2-3 module, such as the coordinates exposed in Table 2 (Figure 2) +/- a root mean square deviation of the structure atoms conserved from the ammoniads thereof of not more than 1.5 Á. An illustrative embodiment of this aspect of the invention is a conventional 3.5-inch diskette, DAT tape or disk unit encoded with a data set, preferably in the PDB format, which comprises the coordinates of Table 2 (Figure 2). ). Figure 3 illustrates an impression of a three-dimensional graphic representation of this polypeptide. In another embodiment, the machine readable data storage medium comprises a data storage material encoded with a first set of machine readable data comprising the Fourier transform of the structural coordinates set forth in Table 2 (Figure 2) ( or again a derivative thereof), and that when using a programmed machine with instructions for using this data, it can be combined with a second set of machine readable data comprising the X-ray diffraction pattern of a molecule or molecular complex to determine at least a portion of the structural coordinates that correspond to the second set of machine readable data. This system can include, for example, a computer comprising a central processing unit ("CPU"), a working memory that can be, for example RAM (random access memory) or "core" memory, mass storage memory (such as one or more disk drives or CD-ROM drives), one or more cathode ray tube display terminals ("CRT") , one or more keyboards, one or more input lines (IP), and one or more output lines (OP), all of which are interconnected by a system bus, bi-directional, conventional. The input equipment, coupled to the computer by the input lines, can be implemented in a variety of ways. The data readable by machines of this invention may be introduced by the use of a modem or modems connected by a dedicated telephone line or data line. Alternatively or additionally, the input equipment may comprise CD-ROM drives or disk drives. In conjunction with the CRT display terminal, a keyboard can also be used as an input device. The output equipment, coupled to the computer by the output lines, can be implemented in a similar way by conventional devices. By way of example, the output equipment may include a CRT display terminal to display a graphic representation of a protein of this invention (or portion thereof) using a program such as QUANTA as described herein. The output equipment may also include a printer, so that a hard copy output, or a disk drive, may be produced to store the output of the system for later use. In the operation, the CPU coordinates the use of the various input and output devices, coordinates mass storage data accesses and accesses to and from the working memory, and determines the sequence of data processing steps. Various programs can be used to process the machine readable data of this invention. The examples of these programs are discussed earlier in this. The algorithms suitable for this purpose are also implemented in programs such as Cast-3D (Chemical Abstracts Service), 3DB Unity (Tripos, Inc.), Quest-3D (Cambridge Crystallographic Data Center), and MACCS / ISIS-3D (Molecular Design Limited). These geometric searches can be augmented by steric search, in which size and form of union site requirements are used to clean up hits that have prohibited dimensions. The programs that can be used to synchronize geometrical and steric requirements in a FRAP FRB search include CAVEAT (Bartlett P., University of California, Berkeley), HOOK (MSI), ALADDIN (Daylight Software) and DOCK (http://www.cmpharm.ucsf.edu/kuntz-/kuntz.html and references cited therein). All of these search protocols can be used in conjunction with existing corporate databases, the Cambridge Structural Database, or chemical database available from chemical suppliers. In one embodiment of the invention, the methods comprise identifying several compounds potentially capable of interacting with the NC 1-2-3 module of NCAM or a fragment thereof, for example, the methods may comprise the identification of a sub-library of compounds that potentially interact with the NCAM 1-2-3 module of NCAM or fragments thereof. This can be achieved using any conventional method. For example, all possible members of a combination library can be listed first, according to available reagents and to the established synthesis chemistries. Then the individual members can be carried separately to a binding site of a MASP-2 polypeptide. Finally, an optimal sub-library can be selected for the synthesis, based on the classification of its coupling scores and / or diversity measures. A computer program for rapid library enumeration has been developed, which includes, for example, CombiLibMaker in Sybyl, Analog, Builder in Cerius2, and the QuaSAR-Co biGen module available in MOE (MOE Software, Chemical Computing Group, 1010 Sherbrooke Street W., Suite 910, Montreal, Canada H3A 2R7). Most of these programs can easily generate all 2D or 3D structures for a combination library containing millions of compounds, using either fragment-based or reaction-based schemes. Other tools are also available within these software packages to reduce the size of a virtual library before coupling. For example, a library listed through CombiLibMaker can be subsequently analyzed with various solutions (available in Sybyl) to provide a sub-library that adequately samples the chemical space. The QuaSAR-CombiDesign is another combination library design tool available in MOE that provides a non-enumerative method for generation of combination libraries, and can, for example, test against five-liter rule using statistical sampling techniques during the creation of the library, create smaller sub-libraries with user-defined property intervals. In principle, the coupling step that follows the creation of libraries can be carried out using any of the available coupling programs such as DOCK or FlexX ©, while the selection of diversity for example can be done using the program of available Daylight, Tripos (diverse solutions), or BC1 or high performance coupling as described for example by Diller and Merz. In another example, a "divide and conquer" approach can be used with this strategy; all product structures in a combination library are seen as having variable substituents linked through one or multiple sites in a common template. The template is first attached to the joint site and only the higher classification postures are saved for further consideration. Then independently the individual substituents are joined in each posture of the template, to assess which substituents can fit well in the binding site. Only these combinations of higher scoring substitutions are further considered and classified to identify the complete product structures that can actually be well coupled at the binding site. This can be done with the help of a suitable computer program such as PRO SELECT, CombiBUILD, CombiDOCK, DREAM ++ and FlexX ©. In one embodiment, the methods of the invention comprise the application of pharmacophores obtained by using active site maps. In the present, the term "active site" is intended to describe a site responsive to interaction with a compound and not a catalytically active site. The method can be for example a computational approach comprising the generation of multiple, promising, structurally diverse test compounds. The search for multiple structural series can be achieved by coupling the information of protein structures with the combination library design using any available method. For example, the "receiver design" method (Murrary et al., 1999) or the method summarized hereinafter, can be used. Methods for counting multiple protein conformations for example as described by Mason et al., 2000) can also be used, including the creation of a dynamic pharmacophore model (as described for example by Carlson et al, 2000) of simulations molecular dynamics. Computer and experimental needle detection approaches can also be used to correlate active sites with molecular fragments, for example as described in Boehm et al., 2000. Any suitable computer program tool for correlating active points (eg, GRID and SITEPOINT can be used with the invention Also MCSS techniques for generating site maps can be used.The suitable methods can comprise for example generation of maps of active sites of protein structure, then all possible pharmacophores of 2-, 3 -and 4- points can be enumerated from the site map and encoded as a bit string (signature) these pharmacophores define a space to be polled by compounds that are selected using the library design informational tool. evaluate the success of approach is the number of active molecular nuclei selected in the design of the librarian ca, with the number of active compounds as a secondary measure. Any suitable algorithm can be used for the generation of site maps, such as algorithms that generate between 10 and 80 characteristic positions for each active site. An example of this method is described for example by Eksterowicz et al J Mol Graph Model. 2002 June; 20 (6): 469.77. The information of the various binding sites of the Ig 1-2-3 module together with the crystal structure of the invention provides a tool for the examination of the biological significance of the contacts Igl to Ig2, Ig1 to Ig3 and Ig2 to Ig3 observed, and for the detection of compounds capable of mimicking the binding of Igl to Ig2, Igl to Ig3, Ig3 to Igl, Ig2 to Ig3 and Ig2 to Ig2 modules of NCAM. The structure of the Igl-2-3 module in solution Alternatively, the 3D structure of the module Igl-2-3 soluble can be determined and used for the detection in silicon of the compounds for the evaluation of their potential to interact with the binding site comprised by the module. NMR spectroscopy can finally be used to solve the structure of proteins in solution. Detection of the compounds The identification of a new compound able to modulate the adhesion, differentiation and / or survival of cells that has NCAM can be carried out in one aspect when detecting a template of the computer model, such as for example the three-dimensional structure of the module Igl-2-3 of NCAM as a crystalline or soluble protein. Accordingly, the invention also relates to the provision of a detection method for selecting a compound capable of modulating the cell differentiation and / or survival of cells displaying NCAM, comprising the steps of i) providing a polypeptide comprising the module Igl-2-3 from NCAM; ii) preparing a crystal protein comprising the polypeptide of (i); (iii) generating a structural model of the Igl-2-3 module of NCAM as a crystal protein of (ii), - (iv) designing a compound in the structure of the model generated in step i); (v) selecting a compound capable of interacting with the homophilic binding site according to the structural model of (iii); (vi) testing the compound of step (vi) in an in vitro or in vivo assay if the compound is capable of modulating the differentiation, adhesion and / or survival of neural cells. The above detection method may comprise, in some embodiments, the use of a computer-generated model of the NCAM Igl-2-3 module, or fragments of this module, such as the Igl, Ig2, Ig3 or Igl-2 modules, or Ig2-3 in a solution. This model can be generated based on the models of the data obtained, for example, of Nuclear Magnetic Resonance spectroscopy of the previous modules. However, preferably, a computer generated model is a structural model of a crystal of the previous modules. The invention provides a computer-generated structural structure model of the Igl-2-3 module for the detection of a compound capable of modulating the adhesion, survival and cellular differentiation dependent on the homologous binding of NCAM. Design of Interactive Compounds Generation of a map of sites The complementary characteristic points to the active site are computed using a computer program tool developed internally. For example, a hydrogen bond donor feature is correlated in the vicinity of a hydrogen bond acceptor at the active site of the protein. The collection of 3D coordinates and marks (acceptors, donors, negatives, positives, hydrophobic and aromatic) is called a site map. Technically, the site map is the union of three separately computed maps, ESMap containing the electrostatic characteristic points (P, N and H) HBMap with characteristic points of hydrogen bonding (D and A) and AroMap containing the characteristic aromatic points (Ar). The electrostatic characteristics map, ESMap, is computed by first using the sphere placement algorithm used in the PASS program (Brady et al., 2000). It generates a set of uniformly distributed points (SondaMapa) in regions of buried volume along the surface of the protein. A subset of points in the Map Probe comprises the characteristic points P, N and H depending on the local electrostatic character of the protein. The molecular mechanical force field CVFF is used to compute the electrostatic potential, fi, at each point i of the Map Probe, together with the average potential f and the average magnitude | f | averaged over all the points in SondaMap. The value of fi determines whether or not point i is included as a characteristic point P, N or H, according to the following definitions. i >; f + l .5 * s (f), i = N characteristic point i > f-l .5 * s (f), i = P characteristic point | f | -1.0 * s (| f |) < | fi | < (| f |) + 1.0 * s (| f |), i = H characteristic point Here s (X) denotes the standard deviation around the mean of the quantity X. This normalizes the point assignments with point assignments with relation to the total electrostatic environment of the active site. This presents uncharged-neutral protein structures (which may result from counter-ions that did not resolve or are present in the crystal structures) from uncharacteristically biased assignments of characteristic points. The map of the hydrogen-binding characteristic, HBMap, is determined by projecting complementary points outward from known hydrogen-bonding atoms of the protein. The resulting superset of points is filtered based on steric shock, insufficient burial and minimum proximity of the similar characteristic point. Ideal hydrogen bonding points are placed based on the average angle and distance as observed in the PDB (see for example table 2 shown in Figure 1). The points that collide with the protein are removed. However, for strength, small position disturbances are applied to retain potentially important hydrogen bonding positions. Bifurcated hydrogen bonding junctions are computed heuristically by investigating whole rings of equally bifurcated points between protein atoms that are considered moderate or strong hydrogen bonding partners. The points in these rings are retained as bifurcated HB points, if they do not violate the conditions of enteric shock, burial and mutual proximity. To construct the final HBMap, the survival sets of the ideal and bifurcated HB points are combined and subjected to filtration based on mutual proximity. The AroMap set of aromatic characteristic points is computed by repeatedly coupling a benzene ring in the active site of the protein and by retaining the centroids of the higher scoring configurations. The protein is represented using a polar-hydrogen CVFF force field. The coupling is done using internal code in local optimization mode. One hundred separate attempts of local coupling with different starting positions are made. Any of the coupled configurations whose score is within an energy window of 5 kcal / mol of the minimum energy configuration is included in AroMap. Again the points are subjected to filtration based on burial and mutual proximity. Conversion of pharmacophores in a subject Pharmacophores are generated based on the characteristic points in the active site by exhaustive enumeration of all subsets of 2-, 3-, and 4- points of the characteristic points. For all the pairs of characteristic points, their distance is pre-computed in 3D space. In order to arrive at a discrete representation of a pharmacophore, the distances are categorized, applying a categorization scheme defined by the user. Chirality is denoted by coding the laterality of 4-point pharmacophores. Each pharmacophore is correlated in a single direction, such that any possible combination of up to four characteristics and distances is represented. The address is taken for a binary representation of pharmacophores, called a subject. The length of the subject is the highest possible address for a coding of a pharmacophore of 4 points, all the bits in the subject are initially set to 0. In order to represent a pharmacophore, the bit and the respective address in the subject are lit (setting to 1) for the representation of the active site, all pharmacophores are listed exhaustively and the respective bits are lit. Union of multiple structure subjects Multiple signatures can be combined. The binary union of multiple signatures produces an individual string 'of bits representing all pharmacophores present in any structure. Any consensus threshold c can be used to define the consensus representation of multiple active sites. That is, a pharmacophore occurs in at least c of the active site conformations. It is pointed out that this way of handling multiple snapshots of active sites is quite convenient. Molecular Signatures The test compounds are encoded as follows. First, conformators are generated for each compound using an internal tool that generates a fairly complete conformational model of the molecule. Characteristics are assigned using a subset of rules based on sub-structure. The pharmacophores are listed from these three-dimensional characteristic positions following the same protocol as for the active site, thus ensuring the compatibility of the binary encodings. However, multiple conformers need to be represented simultaneously. This is done by rolling up the exhaustive enumeration of the pharmacophores for an individual conformer in an additional handle on all the conformers of a compound. That is to say, any pharmacophore in any conformer of a compound is represented by turning on the respective bit in the subject. Masking of molecular signature With the binary representation of the active site and the binary representation of the molecules that are defined analogously, the meaning of a bit at a certain address is the same (the same pharmacophore, within the tolerances of the categorization of the distances). Therefore, the representation of a design space accounts for the masking of all the subjects of the molecule by the subject of the active site. The masking of a subject means taking the logical and the bits of the subject of the site and the subject of the molecule. For a given molecule the bits representing pharmacophores not present in the active site are turned off, while the bits of the pharmacophores in the active site can either be switched on or off, depending on their presence or absence in the molecules. In this way, only the pharmacophore space defined by the active site is taken into account. Informative library design The informative library design is a molecule selection strategy that optimizes the information return for a given virtual library. The objective is to detect a set of characteristics (pharmacophore) that determine the activity against a particular test compound. The informative design helps to select a set of compounds such that the resulting subset will interrogate the test compound in different ways but without overlapping. Molecules are selected for detection synthesis such that each pharmacophore in the design space has a unique pattern of occurrence in the molecules of the set. This unique "code" allows the identification and retention of important pharmacophores when the set of compounds is assessed, despite the actual experimental result. This is in contrast to methods of diversity that seek to produce a unique pattern of pharmacophore occurrences in each molecule. Given a design space, the algorithm seeks to optimize the decoding of as many pharmacophores as possible, with the smoothest distribution through the size of the pharmacophore classes. A class of pharmacophore refers to the set of pharmacophores that have the same code or pattern. It is pointed out that the optimal solution is a set of compounds that allows decoding each individual pharmacophore. However, this may not be possible due to mixing of source, bit ratio or unlimited selection size. The cost function for unrestricted optimization in terms of molecule selection is the entropy of the class distribution. Entropy is given by c l C i | , C i l H -? 1 ln tí f f where H is the entropy of the characteristic classes, C is the number of different classes, f is the number of features in the design space | c | is the size of class i.

During the course of the optimization, molecules are selected, such as to optimize H. Test A compound selected by silicon detection of the above is to be further tested if it has the ability to modulate cell adhesion, differentiation and / or cell survival presenting NCAM. Biological assays for testing a capacity of the compounds to modulate the adhesion, differentiation and / or survival of NCAM-presenting cells are well known in the art. In particular, the assays described in WO 03020749, WO 0247719, WO 03016351 and in the present application can be used. The test of the identified compound (vi) can be carried out in some embodiments additionally or alternatively by using the test method described above. Compound A compound of the present invention is preferably selected by any of the above detection methods. According to the invention, a selected compound is a candidate compound. The term "candidate compound" is intended to make a compound capable of i) interacting with the Igl module of NCAM, and in this way imitate and / or modulate the interaction between the Igl and Ig3 modules of NCAM, where the modules are of two individual NCAM molecules and / or ii) interact with the NC3 Ig3 module, and thus mimic and / or modulate the interaction between the Ig3 and Igl modules of? CAM, where the modules are of two individual molecules? / or iii) interact with the Ig2 module of? CAM, and in this way imitate and / or modulate the interaction between the Ig2 and Ig3 modules of? CAM, where the modules are of two individual NCAM molecules and / or iv) interact with the NCAM Ig3 module, and thus mimic and / or modulate the interaction between the NCAM Ig3 and Ig2 modules, where the modules are of two individual NCAM molecules and / or v) interact with the NCAM Ig2 module, and in this way imitate and / or modulate the interaction between the modules Ig2 and Ig2 of NC AM, where the modules are of two individual NCAM molecules. A candidate compound, which is capable of at least one of the above interactions, is in accordance with the invention also capable of modulating the differentiation, adhesion and cell survival mediated by homologous binding of NCAM through the homophilic binding site described herein. . In a preferred embodiment, a candidate compound is able to interact with the Igl module of NCAM, and thus mimic and / or modulate the interaction between the Igl and Ig3 modules of NCAM, where the modules are of two individual NCAM molecules, and thus modulate cellular differentiation, adhesion and survival mediated by the homologous binding of NCAM through the homophilic binding site of the invention. In another preferred embodiment, a candidate compound is capable of interacting with the NC3 Ig3 module, and thus mimic and / or modulate the interaction between the Ig3 and IgG modules of NCAM, wherein the modules are of two individual NCAM molecules, and thus modulate cellular differentiation, adhesion and survival mediated by the homologous binding of NCAM through the homophilic binding site of the invention. A candidate compound is able to interact with the NCAM Ig2 module, and thus mimic the interaction between the NCAM Ig2 and Ig3 modules, where the modules are from two individual NCAM molecules, and thus modulate the differentiation, adhesion and cell survival mediated by the homologous binding of NCAM through the homophilic binding site of the invention is another preferred embodiment of the invention. In yet another preferred embodiment, a candidate compound is capable of interacting with the NC3 Ig3 module, and thereby mimic and / or modulate the interaction between the IgM and Ig2 modules of NCAM, wherein the modules are of two individual NCAM molecules , and in this way modulate cell differentiation, adhesion and survival mediated by the homophilic union of? CAM through the homophilic binding site of the invention. In yet another preferred modality, a candidate compound is able to interact with the Ig2 module of? CAM, thereby mimicking and / or modulating the interaction between the IgAM and Ig2 modules of NCAM, where the modules are of two individual NCAM molecules, and thus modulate cellular differentiation, adhesion and survival mediated by homologous binding of NCAM through the homophilic binding site of the invention. Other preferred embodiments of the invention relate to i) candidate compounds, which are capable of simultaneous interaction with ammonia residues of the Igl and Ig3 modules of the same NCAM molecule and thus mimic and / or modulate the interaction between the Igl modules Ig3 and Ig3 to Igl of two individual NCAM molecules that interact through these modules, ii) candidate compounds, which are capable of simultaneous interaction with ammonia residues of the Igl and Ig2 modules of the same NCAM molecule and thus mimic and / or modulate the interaction between the Igl to Ig3 and Ig2 to Ig3 modules of two individual NCAM molecules interacting through these modules, iii) candidate compounds, which are capable of simultaneous interaction with ammonia residues of the Igl and Ig3 modules of the same NCAM molecule and thus mimic and / or modulate the interaction between the Igl to Ig3 and Ig3 to Ig2 modules of two individual NCAM molecules that i They interact through these modules, iv) candidate compounds, which are capable of simultaneous interaction with ammonia residues of the Igl and Ig2 modules of the same NCAM molecule and thus mimic and / or modulate the interaction between the Igl to Ig3 modules and Ig2 to Ig2 of two individual NCAM molecules interacting through these modules, v) candidate compounds, which are capable of simultaneous interaction with ammonia residues of the Ig2 and Ig3 modules of the same NCAM molecule and thus mimic and / or modulate the interaction between Ig2 to Ig3 and Ig3 to Igl modules of two individual NCAM molecules interacting through these modules, vi) candidate compounds, which are capable of simultaneous interaction with ammonia residues of the Ig2 and Ig3 modules of the same NCAM molecule and thus mimic and / or modulate the interaction between the Ig2 to Ig2 and Ig3 to Igl modules of two individual NCAM molecules that interact through s of these modules, vii) candidate compounds, which are capable of simultaneous interaction with ammonia residues of the Ig2 and Ig3 modules of the same NCAM molecule and thus mimic and / or modulate the interaction between the Ig2 to Ig3 and Ig3 modules to Igl of two individual NCAM molecules that interact through these modules, viii) candidate compounds, which are capable of simultaneous interaction with ammonia residues of the Ig2 and Ig3 modules of the same NCAM molecule and thus mimic and / or modulate the interaction between the Ig2 to Ig3 and Ig3 to Igl modules of two individual NCAM molecules that interact through these modules. The candidate compound can be any compound, which is capable of the above interactions. This compound can be selected for example from the group comprising libraries of combination of peptides, lipids, carbohydrates or other organic molecules, or co-polymers of amino acids with other organic compounds. In a preferred embodiment, the candidate compound of the invention is a peptide. Alternatively, the compound can be an antibody molecule capable of selective binding to an epitope located within or in close proximity to the binding site. Close proximity is defined herein as a distance of about 50 to 500 A between a residue of amino acids of the epitope and a residue of amino acids from the binding site. It also refers to an antibody molecule, which binds to a distant epitope (at a distance of more than 500 Á from a residue of ammonia from binding site), and binding that leads to a conformational change in the Igl-2 module -3 which thus influences homophilic binding through the binding site. A preferred candidate compound is a compound comprising a sequence of amino acids derived from the binding site described herein. By "derivative" is meant that the amino acid sequence comprises a fragment of the sequence of amino acids ig of the Igl-2-3 module of NCAM, this fragment comprising the binding site or a part of the binding site, or an amino acid sequence comprises a sequence of ammonia residues that are homologous to the residues comprised in the interaction between two individual NCAM molecules through the binding site . The homology of amino acid residues may be about 60%, more preferred is about 70% or even more preferred is about 80%, such as for example 90%, and most preferred is about 100%. The homology of one amino acid residue to another is defined as before. In this manner, a preferred candidate compound may comprise a sequence derived from the Igl module and / or Ig2 module and / or NC3 Ig3 module. Unlimited examples of these compounds may be the compounds identified in the present application as SEQ ID Nos: 1-20, 40-43. Thus, the present invention provides in one embodiment a compound having the amino acid sequence WFSPNGEKLSPNQ set forth in SEQ ID NO: 1. In another embodiment, a compound of the invention is one having the amino acid sequence YKCWTAEDGTQSE set forth in SEQ ID. NO: 2. In yet another embodiment, the invention provides a compound having the amino acid sequence TLVADADGFPEP set forth in SEQ ID NO: 3. In yet another embodiment, the invention provides a compound having the amino acid sequence QIRGIKKTD set forth in SEQ ID NO. NO: 4. In yet another embodiment, the invention provides a compound having the DVR amino acid sequence set forth in SEQ ID NO: 5. In yet one embodiment, the compound of the invention is one having the amino acid sequence RGIKKTD discussed in FIG. SEQ ID NO: 6. In still a further embodiment, the invention provides a compound having the amino acid sequence DVRRGIKKTD set forth in SEQ ID NO: 7. still another aspect, the invention relates to a compound having the amino acid sequence KEGED set forth in SEQ ID NO: 8. In yet another aspect, a compound is one having the amino acid sequence IRGIKKTD set forth in SEQ ID NO: 9. The invention further provides a compound having the amino acid sequence KEGEDGIRGIKKTD set forth in SEQ ID NO: 10.

In addition, in another embodiment, the invention provides a compound having the amino acid sequence DKNDE set forth in SEQ ID NO: 11. In yet another embodiment, the invention relates to a compound having the amino acid sequence TVQARNSIVNAT set forth in SEQ ID NO. 12. In yet another embodiment of the invention, the compound is the one having the ammonia sequence SIHLKVFAK set forth in SEQ ID NO: 13. In yet another embodiment, the compound is the one having the ammonia sequence LSNNYLQIR set forth in SEQ ID NO. : 14. In a further embodiment, the invention provides a compound having the amino acid sequence RFIVILS? NYLQI set forth in SEQ ID? O: 15. In addition, in yet another embodiment, the invention provides a compound having the amino acid sequence KKDVRFIVLS. ?? YLQI exposed in SEQ ID NO. 16. Additionally, in yet another embodiment, the invention provides a compound having the amino acid sequence QEFKEGEDAVIV set forth in SEQ ID NO: 17. The invention further provides a compound having the amino acid sequence KEGEDAVIVCD set forth in SEQ ID? O: 18 In other embodiments, the invention relates to compounds having amino acid sequences GEISVGESKFFL (SEQ ID NO: 19) KHIFSDDSSELTIRNVDKNDE (SEQ ID NO: 20) AFSPNGEKLSPNQ (SEQ ID NO: 40) AKSWTAEDGTQSE (SEQ ID NO: 41) DVRRGIKKTD (SEQ ID NO: 42) OR QIRGIKKTD (SEQ ID NO: 43). The above sequences can also be considered as preferred candidate compounds of the invention. Also included within the scope of the invention are fragments or variants of these sequences as candidate compounds capable of the interactions and / or sequences of the original sequences, especially the sequences, which are derived from or are homologous. The sequences identified above according to the invention represent different fragments in a homologous binding site of NCAM in the Igl-2-3 module are capable of modulating the differentiation and / or survival of a cell displaying NCAM. According to the invention, the sequences identified above can be used for the manufacture of a medicament for the treatment of a condition or disease wherein the modulation of the homophilic interaction of NCAM will lead to improvement or rescue. Additionally, the above sequences can be used for the production of an antibody capable of recognizing and specifically binding to the binding site of the invention. This antibody according to the invention is capable of at least one of the biological activities of the compound described above and can be advantageously used in some embodiments for medical applications such as the compound of the invention. Production of peptide sequences The peptide compounds of the present invention can be prepared by any conventional synthesis method, recombinant DNA technologies, enzymatic cleavage of full-length proteins from which the peptide sequences are derived, such as for example NCAM molecules of different origin of species, or a combination of these methods. Recombinant preparation The recombinant preparation is a preferred method for the production of long chain polypeptide sequences, such as for example the Igl-2-3 module, or individual CAM modules, such as Igl, Ig2 or Ig3, or combinations thereof. same as Igl-2, Igl-3, or Ig2-3. However, the shorter peptide fragments of 15-50 amino acids long comprising the sequences derived from the binding site of the invention can also be prepared recombinantly using any of the technologies described below. The DNA sequence encoding a peptide or the corresponding full-length protein from which the peptide originates, or a fragment thereof, can be prepared synthetically by standard established methods, for example, the phosphoamidine method described by Beaucage and Caruthers, 1981, Tetrahedron Lett. 22: 1859-1869, or the method described by Matthes et al., 1984, EMBO J. 3: 801-805. According to the phosphoamidine method, oligonucleotides are synthesized, for example, in an automatic DNA synthesizer, purified, fixed, ligated and cloned into suitable vectors. The DNA sequence encoding a peptide can also be prepared by fragmenting DNA sequences coding for the corresponding full-length protein, for example NCAM protein, using ADβase I according to a normal protocol (Sambrook et al. al., Molecular cloning: Laboratory manual, 2nd ed., CSHL Press, Cold Spring Harbor, 1989. AD, which codes for a full-length protein can be fragmented alternatively using specific restriction endonucleases. Fragments of AD? are further purified using standard procedures described in Sambrook et al., Molecular cloning: A Laboratory Manual, 2 rd ed., CSHL Press, Cold Spring Harbor,? Y, 1989.

The DNA sequence encoding a full-length protein can also be of genomic or cDNA origin, for example obtained by preparing a genomic or cDNA library and by detecting DNA sequences that encode all or part of the protein in length complete by hybridization using synthetic oligonucleotide probes according to standard techniques (compare Sambrook et al., Molecular cloning: A Laboratory Manual, 2 rd ed., CSHL Press, Cold Spring Harbor, NY, 1989). The DNA sequence can also be prepared by polymerase chain reaction using specific primers, for example as described in US 4,683,202 or Saiki et al., 1988, Science 239: 487-491. The DNA sequence is then inserted into a recombinant expression vector, which can be any vector, which can be conveniently subjected to recombinant DNA procedures. The choice of vector will be more frequently understood from the host cell into which it is to be introduced. In this manner, a vector can be a vector of autonomous replication, ie a vector that exists as an extrachromosomal entity, the replication of which is independent of chromosomal replication, for example, a plasmid. Alternatively, the vector may be one which, when introduced into a host cell, is integrated into the genome of the host cell and replicated together with the chromosomes in which it has been integrated. In the vector, the DNA sequence encoded for a peptide or a full length protein must be operably linked to a suitable promoter sequence. The promoter can be any DNA sequence, which shows transcriptional activity in the host cell of choice and can be derived from genes and encoded for proteins homologous and heterologous to the host cell. Examples of suitable promoters for directing the transcription of the coding DNA sequence in mammalian cell are the SV 40 promoter.

(Subramani et al., 1981, Mol Cell Biol 1: 854-864), the MT-1 promoter (metallothionein gene (Palmiter et al., 1983, Science 222: 809-814) or the major late promoter of adenovirus 2. A promoter suitable for use in insect cells is the polyhedrin promoter (Vasuvedan et al., 1992, FEBS Lett 311: 7-11). Promoters suitable for use in yeast host cells include promoters of yeast glycolytic genes (Hitzeman et al., 1980, J. Biol. Chem. 255-12073-12080, Alber and Kawasaki, 1982, J. Mol.

Appl. Gen. 1: 419-434) or alcohol-dehydrogenaza genes (Young et al., 1982, in Genetic Engineering of Microorganisms for Chemicals, Hollaender et al., Eds., Plenum Press, New York), or TTll (US 4,599,311) or ADH2-4C (Russell et al., 1983) Nature 304: 652-654). Suitable promoters for use in filamentous fungal host cells are for example the ADH3 promoter (McKnight et al., 1985, EMBO J. 4: 2093-2099) or the tpiA promoter. The coding DNA sequence can also be operably connected to a suitable terminator, such as the growth hormone terminator (Palmiter et al., Op.cit.) Or (for fungal hosts) the TPI1 promoters (Alber and kawasaki, op cit). The vector may further comprise elements such as polyadenylation signals (e.g., SV 40 or 5 Elb region, adenovirus), transcriptional enhancer sequences (e.g., SV 40 enhancer) and tranductional enhancer sequences, e.g. encode for VA RNAs of adenovirus. The recombinant expression vector may further comprise a DNA sequence that allows the vector to replicate in the host cell in question. An example of this sequence (when the host cell is a mammalian cell) is the SV 40 origin of replication. The vector may also comprise a selectable marker, for example a gene, the product of which complements a defect in the host cellulose. , such as the gene encoding dihydrofolate reductase (DHFR) or one that confers resistance to a drug, for example, neomycin, hydromycin or methotrexate.

The methods used to ligate the DNA sequences encoding the full-length peptides or proteins, the promoter and the terminator, respectively, and to insert them into suitable vectors containing the information necessary for replication, are well known to the skilled person. in the art (compare, for example, Sambrook et al., op cit.) To obtain recombinant peptides of the invention, the coding DNA sequences can be usefully fused with a second peptide coding sequence and a coding sequence. of protease cleavage site, which gives a DNA construct encoding the fusion protein, wherein the protease cleavage site coding sequence positioned between the HBP fragment and the second peptide coding DNA, inserted in a recombinant expression vector, and expressed in recombinant host cells. In one embodiment, this second peptide selected in a manner 'enunciative and without limitation of the group comprising glutathione-S-reductase, calf thymosin, bacterial thioredoxin or natural or synthetic variants of human ubiquitin, or peptides thereof. In another embodiment, a peptide sequence comprising a protease cleavage site may be factor Xa, with the amino acid sequence IEGR, enterokinase, with the amino acid sequence DDDDK, thrombin, with the amino acid sequence LVPR / GS, or Acharomba ter lyticus, with the amino acid sequence XKX, cleavage site. The host cell into which the expression vector is introduced may be any cell that is capable of expression of full-length peptides or proteins, and is preferably a eukaryotic cell, such as invertebrate cells (insects) or cells. of vertebrate, for example, Xenopus laevis oocytes or mammalian cells, in particular insect and mammalian cells. Examples of suitable mammalian cell lines are the cell lines HEK293 (ATCC CRL-1573), COS (ATCC CRL-1650), BHK (ATCC CRL-1632, ATCC CCL-10) or CHO (ATCC CCL-61). Methods for transfecting mammalian cells and for expressing DNA sequences introduced into cells are described in for example Kaufman and Sharp, J. Mol. Biol. 159, 1982, pp. 601-621; Southern and Berg, 1982, J. Mol. Appl. Genet 1: 327-341; Loyter et al., 1982, Proc. Nati Acad. Sci. USA 79: 422-426; Wigler et al., 1978, Cell 14: 725; Corsaro and Pearson, 1981, in Somatic Cell Genetics 7, p. 603; Graham and van der Eb, 1973, Virol. 52: 456 and Neumann et al., 1982, EMBO J. 1: 841-845. Alternatively, fungal cells (including yeast cells) can be used as host cells. Examples of suitable yeast cells include cells of Saccharomyces spp. or Schizosaccharomyces spp. , in particular strains of Saccharomyces cerevisiae. Examples of other fungal cells are filamentous fungal cells, for example Aspergillus spp. or Neurospora spp. , in particular strains of Aspergillus oryzae or Aspergillus niger. The use of Aspergillus spp. for the expression of • proteins is described in for example EP 238,023. The medium used to culture the cells can be any conventional means suitable for culturing mammalian cells, such as a serum-containing medium or is free of serum containing appropriate supplements, or a suitable medium for culturing insect, yeast or fungal cells. Suitable media are available from commercial suppliers or can be prepared according to published recipes (for example, in the catalogs of the American Type Culture Collection). The peptides or full length proteins produced recombinantly by the cells can then be recovered from the culture medium by conventional methods including separation of the host cells from the medium by centrifugation or filtration, precipitation of the protein components of the supernatant or filtering by means of a salt., for example, ammonium sulfate, purification by a variety of chromatographic methods, for example, HPLC, ion exchange chromatography, affinity chromatography, or the like. Synthesis preparation The synthesis preparation is preferred when the short sequences of 3 to 50 amino acids are related. Methods for the synthetic production of peptides are well known in the art. Detailed descriptions as well as practical advice for producing synthetic peptides can be found in Synthetic Peptid.com: A User's Guide (Advances in Molecular Biology), Grant GA ed., Oxford University Press, 2002, or in: Pharmaceutical Formulation: Development of Peptides and Proteins, Frokjaer and Hovgaard eds., Taylor and Francis, 1999. Peptides can be synthesized, for example, by using Fmoc chemistry and cysteines protected with Acm. After purification by reverse phase HPLC, the peptide can be further processed to obtain for example C- or N-terminal modified isoforms. Methods for cyclization and terminal modification are well known in the art and are described in detail in the manuals cited above. In a preferred embodiment, the specific sequences of the invention are synthetically produced, in particular, by the sequence-assisted peptide synthesis method (SAPS). Peptides can be synthesized either batchwise in a polyethylene container equipped with a polypropylene filter for filtration or in the continuous flow version of the polyamide solid phase method (Dryland, A and Sheppard, R.C., (1986) J. Chem. Soc. Perkin Trans. I, 125-137). In a fully automated peptide synthesizer (Cameron et al., (1987), J. Chem.

Soc. Chem. Commun, 270-272) using 9-fluorenylmethyloxycarbonyl (Fmoc) or tert-butyloxycarbonyl (Boc) as the protecting group of N-a-amino and suitable common protection groups for the functional groups of the side chain. Pharmaceutical Composition Once the candidate compounds of the invention have been identified, it is further within the scope of the invention to provide a pharmaceutical composition comprising one or more compounds. In the present context, the term "pharmaceutical composition" is used in a manner comparable to the term "medication." The invention further relates to a pharmaceutical composition capable of preventing the death of cells that present NCAM, of promoting cell differentiation of neural cells and neural plasticity, and of stimulation of survival and regeneration of cells presenting NCAM and / or cells that present NCAM ligand in various tissues and organs in vivo or in vi tro as discussed herein, the composition comprising a quantity. effective of one or more of the compounds described above. The medicament of the invention may comprise an effective amount of one or more of the compounds as defined above in combination with pharmaceutically acceptable additives. This medicine can be formulated in a manner suitable for oral, percutaneous, intramuscular, intravenous, intracranial, intrathecal, intracerebroventricular, intranasal or pulmonary administration. The present invention also relates to a medicament for the treatment of diseases and conditions of the peripheral central nervous system, of the muscles or of various organs, wherein the medicament comprises an effective amount of one or more of the compounds as defined above or a composition as defined above in combination with pharmaceutically acceptable additives or carriers. This medicine can be formulated appropriately for oral administration, '' percutaneous, intramuscular, intravenous, intracranial, intrathecal, intracerebroventricular, intranasal or pulmonary. Formulation The strategies in the development of drug formulation and compositions based on the compounds of the present invention correspond in general to formulation strategies for any other protein-based drug product. Potential problems and the guidance required to overcome these problems are discussed in several textbooks, for example "Therapeutic Peptides and Protein Formulation. Processing and Delivery Systems", Ed. A.K. Banga, Technomic Publishing AG, Basel, 1995. Injectable products are usually prepared either as liquid solutions or suspensions, solid forms suitable for solution in, or suspension in, liquid before injection. The preparation can also be emulsified. The active ingredient is often mixed with excipients, which are pharmaceutically acceptable and compatible with the active ingredient. Suitable excipients are for example water, saline, dextrose, glycerol, ethanol or the like, and combinations thereof. In addition, if desired, the preparation may contain minor amounts of auxiliary substances such as wetting or emulsifying agents, pH buffering agents, which improve the effectiveness or transport of the preparation. The formulations of the compounds of the invention can be prepared by techniques known to the person skilled in the art. The formulations may contain pharmaceutically acceptable carriers and excipients including microspheres, liposomes, microcapsules, nanoparticles or the like. Administration For many indications, a localized or substantially localized application is preferred. The compounds are used in particular in combination with a prosthetic device such as a prosthetic nerve guide. In this way, in a further aspect, the present invention relates to a prosthetic nerve guide, characterized in that it comprises one or more of the compounds or the composition defined above. The nerve guides are known in the art. The preparation can be administered suitably by injection, optionally at the site, where the active ingredient will exert its effect. Additional formulations that are suitable for other modes of administration include suppositories, nasal, pulmonary and, in some cases, oral formulations. For suppositories, traditional binders and carriers include polyalkylene glycols or glycerides. These suppositories can be formed of mixtures containing the active ingredients in the range of 0.5 to 10%, preferably 1-2%. Oral formulations include excipients normally employed such as for example pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharins, cellulose, magnesium carbonate, and the like. These compositions take the form of solutions, suspensions, tablets, pills, capsules, sustained-release formulations or powders and generally contain 10-95% of the active ingredients. Preferably 25-70%. Other formulations are suitable for nasal and pulmonary administration, for example inhalers and aerosols. The active compound can be formulated as neutral or salt forms. Pharmaceutically acceptable salts include acid addition salts (formed with the free amino groups of the peptide compound) and which are formed with inorganic acids such as for example hydrochloric or phosphoric acids, or organic acids such as acetic acid, oxalic acid, tartaric acid , mandelic acid, and the like. Salts formed with free carboxyl groups can also be derived from inorganic bases such as for example, sodium, potassium, ammonium, calcium or ferric hydroxides, and organic bases such as isopropylamine, trimethylamine, 2-ethylamino-ethanol, histidine, procaine, and similar. The preparations are administered in a manner compatible with the dosage formulation, and in an amount that will be therapeutically effective. The amount to be administered depends on the subject to be treated, including, for example, the weight and age of the subject, the disease to be treated and the stage of the disease. Suitable ranges of doses are of the order of several • hundreds of μg of active ingredient for administration with a preferred range from about 0.1 μg to 100 mg, such as in the range from about 1 μg to 100 mg, and especially in the range from about 10 μg to 50 mg. The administration can be formed once or can be followed by subsequent administrations. The dose will also depend on the route of administration and will vary with the age and weight of the subject to be treated. A preferred dose that is given in the range of 0.5 mg to 50 mg per 70 kg of body weight. Some of the candidate compounds of the present invention are sufficiently active, but for others, the effect will improve if the preparation further comprises pharmaceutically acceptable additives and / or carriers. These additives and carriers will be known in the art. In some cases, it will be advantageous to include a compound, which promotes the distribution of the active substance to its target. In another embodiment, it may be advantageous to administer the candidate compounds according to the invention for other substances to obtain a synergistic effect. Examples of other substances may be a growth factor, which may induce differentiation, or a hormone, or a cell transplant, including stem cell transplantation, or gene therapy immunotherapy. In some cases, it will be necessary to administer the formulation several times. The administration can be a continuous infusion, such as infusion or intra-ventricular administration in more doses, such as, more doses per day, daily, more doses per week, or weekly. It is preferred that drug administration be initiated before or immediately after the individual has been subjected to factors that can lead to cell death. Preferably, the drug is administered within 8 hours from the start of the factor, such as the space of 5 hours from the start of the factor. Many of the compounds exhibit a long-term effect, whereby the administration of the compounds can be conducted at long intervals, such as a week or two weeks. In one embodiment of the invention, the administration of the present compound can be immediately after an acute injury, such as an acute attack, or at most 8 hours after the therapy so that the present compound has a stimulatory effect on survival cell phone. Furthermore, in cases where proliferation and / or differentiation are related, the administration according to the invention is not time-dependent, that is, it can be administered at any time. Production of a pharmaceutical product In another aspect, the invention relates to a process for producing a pharmaceutical composition, comprising mixing an effective amount of one or more of the compounds of the invention, or a pharmaceutical composition according to the invention with one or more additives to pharmaceutically acceptable carriers, and administering an effective amount of at least one of the compound, or the pharmaceutical composition to subject. In still a further aspect the invention relates to a method for treating an individual suffering from one or more of the diseases discussed above by administering to the individual a compound as described herein or a pharmaceutical composition comprising the compound. Drug The candidate compounds of the invention can be used advantageously to treat cells that exhibit NCAM molecules. NCAM is expressed in a variety of cells of the body where it can serve as an adhesion molecule, receptor and / or as a ligand, depending on the type 'cellular and / or cellular environment. The present inventors discovered that candidate compounds that bind to different parts of the binding site described herein may have different effects on cell adhesion, differentiation and / or survival and therefore the compounds are suggested herein for use as direct stimulators of cell differentiation and survival, such as differentiation and survival of neural cells, and as modulators of NCAM function in neural plasticity, such as for example synaptic plasticity. In this manner, the candidate compounds of the invention can be used in the manufacture of medicaments to be used to treat various pathological conditions of the peripheral and / or central nervous system and / or muscle of other tissues expressing? CAM, such as trauma and / or disease, as well as conditions in which a fine modulation of the CAM function, such as memory and learning stimulation, may be beneficial. In this way, a candidate compound of the The invention can be for the manufacture of a medicament for the treatment of cells presenting CAM and / or CAM ligands, normal, degenerated or damaged. In particular, the compound and / or pharmaceutical composition of the invention can be used in the treatment of clinical conditions, such as neoplasms, such as malignant neoplasms, benign neoplasms, carcinoma in situ and neoplasms of uncertain behavior, diseases of endocrine glands, such such as diabetes mellitus, psychosis, such as senile and presenile organic psychotic conditions, alcoholic psychosis, drug psychosis, momentary organic psychotic conditions, Alzheimer's disease, cerebral lipidosis, epilepsy, general paralysis (syphilis), hepatolenticular degeneration, Huntington's chorea, disease of Jacob-Creutzfeldt, multiple sclerosis, Pick's disease of the brain, syphilis, Schizophrenic disorders, affective psychosis, neurotic disorders, personality disorders, including character neurosis, non-psychotic personality disorder associated with organic brain syndromes, paranoid personality disorder , p fanatical personality, paranoid personality (disorders), paranoid traits, deviations and sexual disorders, mental retardation, nervous system disease and organs of perception, cognitive abnormalities, inflammatory disease of the central nervous system, such as meningitis, encephalitis, brain degeneration, such such as Alzheimer's disease, Pick's disease, senile degeneration of the brain, communicating hydrocephalus, obstructive hydrocephalus, Parkinson's disease including other additional pyramidal diseases and abnormal movement disorders, spino-cerebellar disease, cerebellar ataxia, Marie's disease, of Sanger-Brown , myoclonic cerebellar dis-synergy, primary cerebellar degeneration, such as spinal muscular atrophy, juvenile spinal muscular family atrophy, in adults, motor neuron disorder, amyotrophic lateral sclerosis, motor neuron disease, progressive bulbar paralysis, pseudobulbar paralysis, sclerosis primary tissue, other anterior horn cell diseases, anterior horn cell diseases, unspecified diseases and other diseases of the spinal cord, syringomyelia and syringobulbia, vascular myelopathies, acute spinal cord infarction (embolic) (non-embolic), thrombosis arterial spinal cord, spinal cord edema, sub-acute necrotic myelopathy, combined-sub-acute degeneration in the spinal cord in diseases classified anywhere, myelopathy, radiation-induced myelitis, drug-induced, autonomic nervous system disorders, disorders of the peripheral, sympathetic, parasympathetic, or vegetative autonomic system, familial dysautonomia [Riley-Day syndrome], peripheral autonomic neuropathy, syncope, or carotid sinus syndrome, cervical sympathetic dystrophy or paralysis, peripheral autonomic neuropathy in disorders classified anywhere, amyloidosis, diseases of the peripheral nervous system, brachial plexus lesions, cervical rib syndrome, costoclavicular syndrome, anterior scalene syndrome, thoracic connection syndrome, brachial neuritis or radiculitis, including neonatal inflammation and toxic neuropathy, including acute infective polyneuritis, Guillain-Barre syndrome, post-infectious polyneuritis, polyneuropathy in collagen vascular disease, disorders affecting multiple structures of the eye, purulent endophthalmitis, ear diseases and mastoid process, chronic heart disease, ischemic heart disease, arrhythmias, diseases in the pulmonary system, abnormalities of organs and soft tissues in newborns, including in the nervous system, complications of the administration of anesthetic sedatives or other sedatives in the abor and childbirth, skin diseases including infection, insufficient circulation problem, injuries, including after surgery, crush injury, burns. Injuries to nerves and spinal cord, including division of nerves, continuity injury (with or without open wound) traumatic neuroma (with or without open wound), traumatic momentary paralysis (with or without open wound), accidental puncture or accidental laceration during procedure medical, optic nerve injury or optical pathways, optic nerve injury, second cranial nerve, optic chiasm lesion, lesion to optical pathways, lesion to visual cortex, nonspecific blindness, injury to other cranial nerves, injury to other nerves and nerves unspecified Poisoning by drugs, medical and biological sources, genetic or traumatic muscle atrophy disorders; or for the treatment of diseases or conditions of various organs, such as degenerative conditions of the gonads, of the pancreas, such as diabetes mellitus I and II, of the kidney, such as nephrosis. CNS / PNS Conditions In another aspect of the invention, the compounds are for the treatment of diseases or conditions of the central and peripheral nervous system, such as post-operative damage of nerves, traumatic nerve damage, damaged myelination of nerve fibers, damage post-ischemic, for example, resulting from an attack, Parkinson's disease, Halzheimer's disease, Huntington's disease, dementias such as multi-infarct dementia, sclerosis, nerve degeneration associated with diabetes mellitus, disorders that affect the cycadian clock or neuropathic tradition. muscle, and schizophrenia, mood disorders, such as manic depression; for the treatment of diseases or conditions of the muscles which include conditions with impaired function of neuromuscular connections, such as after organ transplantation, or such as genetic or traumatic muscle atrophic disorders; or for the treatment of diseases or conditions of various organs, such as degenerative conditions of the gonads, of the pancreas such as diabetes mellitus type I and II, of the kidney such as nephrosis of the heart and intestine, and for the treatment of postoperative damage of nerves, traumatic nerve damage, damaged myelination of nerve fibers, post-ischemic damage, for example resulting from stroke, Parkinson's disease, Alzheimer's disease, dementias such as multi-infarct dementia, sclerosis, nerve damage associated with diabetes mellitus, disorders that affect the circadian clock or neuromuscular transmission, and schizophrenia, mood disorders such as manic depression.

Prevention of cell death In addition, candidate compounds according to the invention can be used to prevent cell death of cells that are implanted or transplanted. This is particularly useful when using compounds that have a long-term effect. In another aspect of the invention, the candidate compounds can be synthesized and segregated from engineered cells with implanted or injected genes. Heart muscles In addition, the candidate compound and / or pharmaceutical composition can be for preventing cell death of heart muscle cells, such as after acute myocardial infarction, or after angiogenesis. In addition, in one embodiment, the compound and / or pharmaceutical composition is for the stimulation of survival of cardiac muscle cells, such as survival after acute myocardial infarction. In another aspect, the compound and / or pharmaceutical composition is for revascularization, such as after lesions. Memory In another aspect, the candidate compound and / or pharmaceutical composition is used for stimulation for the ability to learn and / or long-term and / or short-term memory.

Regeneration In one aspect of the invention, the treatment by the use of the candidate compounds according to the invention is useful for the stimulation of regenerating cells that are regenerating or at risk of dying due to a variety of factors, such as traumas. and injuries, acute diseases, chronic diseases and / or chronic disorders, in particular degenerative diseases that normally lead to cell death, other external factors such as medical and / or surgical treatments and / or diagnostic methods that can cause free radical formation or that otherwise have cytotoxic effects, such as X-rays and chemotherapy. Prion Disease The candidate compound for a pharmaceutical composition comprising the same can also be used to treat Prion diseases. The NCAM has been shown to be a molecular interaction partner with the cellular prion protein. For wound healing It is also within the scope of the invention to use the candidate compound and / or pharmaceutical composition for the promotion of wound healing. The present compounds are capable of interfering with cell adhesion and thereby promoting the wound healing process.

Cancer The invention further describes the use of the candidate compound and / or pharmaceutical composition of the cancer treatment. NCAM regulates motility and inhibits the spread of cancer cells. References Atkins, A.R., Osborne, M.J., Lashuel, H.A., Edelman, G.M., Wright, P.E., Cunningham, B.A., and Dyson, H.J. (1999) . Association between the first two immunoglobulin-like domains of the neural cell adhesion molecule? -CAM. FEBS Lett. 451, 162-168. Atkins, A.R, Chung, J., Deechongkit, S., Little, E.B., Edelman, G.M. , Wright, P.E., Cunningham, B.A., and Dyson, H.J. (2001). Solution structure of the third immunoglobulin domain of the neural cell adhesion molecule? -CAM: can solution studies define the mechanism of homophilic binding? J. Mol. Biol. 311, 161-172. Becker, J.W. , Erickson, H.P., Hoffman, S., Cunningham, B.A., and Edelman, G.M. (1989). Topology of cell adhesion molecules. Proc. Nati Acad. Sci. USA 86, 1088-1092. Berezin, V., Bock, E., and Poulsen, F.M. (2000). The neural cell adhesion molecule. Curr. Opin. Drug Discovery Dev. 3, 605-609. Bork, P., Downing, A.K., Kieffer, B., and Campbell, I.D. (nineteen ninety six). Structure and distribution of modules in extracellular proteins. Q. Rev. Biophys. 29, 119-167. Brieher, W.M., Yap, A.S., and Gumbiner, B.M. (nineteen ninety six). Lateral dimerization is required for the homophilic binding activity of C-cadherin. J Cell Biol. 135, 487-496. Brunger, A.T. , Adams, P.A., Clore, G.M. , Of the year, W.L., Gros, P., Grosse-Kunstleve, R.W. , Jiang, JS, Kuszewski, J., Nilges, M., Pannu, N.S., Read, R.J., Rice, L.M., Simonson, T., and Warren, G.L. (1998). Crystallography & NMR system: A new software suite for macromolecular structure determination. Acta Cryst. D54, 905-921. Casasnovas, J.M. , Stehle, T., Liu, J.H., Wang, J.H., and Springer, T.A. (1998). A dimeric crystal structure for the? -terminal two domains of intercellular adhesion molecule-1. Proc. Nati Acad. Sci. USA. 95, 4134-4139. Chothia, C, and Jones, E.Y. (1997). The molecular structure of cell adhesion molecules. Annu. Rev. Biochem. 66, 823-862. Cole, G.J., and Akeson, R. (1989). Identification of a heparin binding domain of the neural cell adhesion molecule N-CAM using synthetic peptides. Neuron 2, 1157-1165. Collaborative Computational Project, number 4. (1994). The CCP4 Suite: Programs for Protein Crystallography. Acta Cryst. D50, 760-763. Covault, J., and Sanes, J.R. (1985). Neural cell adhesion molecule (NCAM) accumulates in denervated and paralyzed skeletal muscles. Proc. Nati Acad. Sci. USA 82, 4544-4548. Conté, L.L., Chothia, C, and Janin, J. (1999). The atomic structure of protein-protein recognition sites. J. Mol. Biol. 285, 2177-98. Cremer, H., Lange, R., Christoph, A., Plomann, M., Vopper, G., Roes, J., Brown, R., Baldwin, S., Kraemer, P., Scheff, S., Barthels, D., Rajewsky, K., and Wille, W. (1994). Inactivation of the N-CAM gene in mice results in size reduction of the olfactory bulb and deficits in spatial learning. Nature 367, 455-459. Cunningham, B.A., Hemperly, J.J., Murray, B.A., Prediger, E.A., Brackenbury, R., and Edelman, G.M. (1987).

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Dimeric association and segmental variability in the structure of human CD4. Nature 387, 527-530. Experimental Part The following is a non-limiting example of the production of the candidate compounds of the invention, a fragment of NCAM comprising the Igl-2-3 module and fragments thereof, such as Igl, Ig2, Ig3, or Igl-2 , or Ig2-3, the description of the crystal protein comprising the Igl-2-3 module, and the biological test of the selected candidate compounds. Production of Igl-2-3 and Ig3 fragments of NCAM Igl-2-3 and Ig3 fragments of NCAM were produced as recombinant proteins in the yeast expression system p. pastoris (Invitrogen). The cDNA fragments coding for Igl-2-3 and rat NCAM Ig-3 (accession number of NCBI NP-113709), corresponding to residues 1-289 and 191-289, respectively, were synthesized by PCR using rat NCAM cDNA as a template. The following DNA primers were used for the cloning of Igl-2-3 and Ig3, respectively: upper (5 '-TCT CTC GAG TTC TGC AGG TAG ATA TTG TT-3') (SEQ ID NO: 37) and lower ( 5 '-AAA CCC GGG TTA CTT TGC AAA GAC CTT-3') (SEQ ID NO: 30), higher (d'GAA TAC GTA ACT GTC CAG GCC AGA C-31) (SEQ ID NO: 31) and lower (5 '-AAA CCT AGG TTA CTT TGC AAA GAC CTT G-31) (SEQ ID NO: 32). The amplified AD? C fragments were sub-cloned into the plasmids pHIL-Sl and pCPIC9K (Invitrogen), respectively. The recombinant plasmids were linearized with the restriction enzymes? Sil and Sacl, respectively, and used for the transformation of the strain His 4 GS-115 (Invitrogen) from P. pastoris. The large-scale production of the recombinant proteins was carried out using a high-density batch fermentation technique in a Biostat B fermentor (B. Braun Biotech Int. GmbH). Igl-2-3 and Ig3 were purified from concentrated and disheveled medium by anion exchange chromatography on a HiTrap Q-Sepharose 5 ml column (Pharmacia), followed by gel fixation chromatography on a HiLoad 16/60 Superdex-75 column ( Pharmacia). Igl-2-3 was enzymatically deglycosylated with P? Gasa-F endo-? -glycosidase (? Ew England Biolabs) at 37 ° C in PBS buffer at pH 7.4. The authenticity of the fragments of the protein was confirmed by sequencing of AD? of the recombinant plasmids, by sequencing the amino acids of the 10-12-terminal residues, and by MALDI-TOF MS. The Igl-2-3 and Ig3 fragments contained respectively two (RV) and five (EAEAY) residues-additional terminals of the cloning vector. The purity of the proteins was at least 95% as estimated by SDS-PAGE.

Production of Igl-2-3 and Ig3 mutants A mutant of Igl-2-3 (Igl-2-3mut) containing substitutions The IA, E16A, and K18A was produced as a recombinant protein in the expression system of yeast of P. pastoris following the procedure described for fragment Igl-2-3. All three substitutions were introduced by PCR using the following DNA primer: upper (5 '-CTG CAG GTA ATT ATT GTT CCC AGC CAA GGA ATCC AGC GTT GGA GCC TCC GCC TTC TTC CTG TGT CAA GTG GCA-3') (SEQ ID NO: 33). Two Ig3 mutants containing the syndications: R198A, D249G, E287A (Ig3mutl) and K285A, F287A (Ig3mut2) were produced as recombinant proteins in the yeast expression system of P. pastoris following the procedure described for the Ig3 fragment. Mutations were introduced by PCR using the following DNA primers: top1 (5 '-AAA TAC GTA ACT GTC CAG GCC GCC CAG AGC ATC GTG-3') (SEQ ID NO: 38), siperior2 (5 '-GGC AGT TCG GCG TTA ACC ATC AGG AAT GTG GAC-3') (SEQ ID NO: 34), and lower (5 '-GGT TAA CGC CGA ACT GTC GCC ACT GAA GAT GTG CTT CTC- 3 ') (SEQ ID NO: 35) for Ig3mutl, and lower (5' -AAA CTT AGG TTA CU TGC TGC GAC TGC GAG GTG GAT GGA GGC ATC-3 ') (SEQ ID NO: 36) for Ig3mut2. The DNA constructs of Igl-2-3mut, Ig3mutl, and Ig3mut2 were verified by DNA sequencing. The folding of the Ig3 module and its mutants, as well as the presence of carbohydrates, was confirmed by one-dimensional proton NMR spectra recorded at 800 MHz on a Varian NMR spectrometer (Varian Inc.) at 25 ° C in PBS buffer pH 7.4. Preparation of peptides The peptides were analyzed using the protection strategy with 9-fluorenylmethoxycarbonyl (Fmoc) in a resin TentaGel (Rapp Polymere) using ammonia protected with Fmoc (Calbiochem-Novabiochem). The peptides were at least 85% pure as estimated by MALDI-TOF MS. All peptides were synthesized with free NH2 and carboxy-amidated COOH groups. Crystallization and data collection Igl-2-3 crystals from NCAM were cultured at 18 ° C using the pendant drop vapor diffusion method, with droplets of equal volumes of protein and reservoir solutions (4 mg with ml "1 in 5 mM Na phosphate, 150 mM NaCl, pH 7.4) The reservoir solution contained 14-17% w / v PEG 4000, 450 mM Li-sulfate, 100 mM Na-acetate, pH 5.2. I2? 2? 2? With one molecule in the asymmetric unit and the cell dimensions of a = 51.5, b = 108.5, and c 149.0 A. The crystals were instantly cooled in liquid nitrogen using 15% v / v glycerol as cryoprotectant. collected two sets of data in the same crystal, high resolution data were collected at 2.0 Á at 120 K in beamline 1711, Max-Lab, Lund, Sweden, and low resolution data were collected at 3.5 Á at 120 K in a Rigaku RU300 rotating anode equipped with a MAR345 image plate detector. they were combined and processed with DENZO / SCALEPACK (Otwinowski and Minor, 1997) and the CCP4 suite of programs (Collaborative Computational Proj ect No. 4, 1994). Determination of structure and refinement The structure was determined by molecular replacement with AmoRe programs (Navaza and Saludjan, 1997) and CNS version 1.0 (Brunger et al., 1998), using the X-ray structures of the IgAM and Igl modules of NCAM (Kasper et al., 2000) as search modules. Initially, the position of the Ig2 module was located using AmoRe. The Igl module was located subsequently using CNS. An electronic density map was calculated based on the phase information of Igl and Ig2. The Ig3 residues gradually accumulated on this map. The interpretation of the map and the construction of the model were carried out using program 0 (Jones et al., 1991). After several cycles of construction and refinement, ARP / wARP version 5.1 (Perrakis et al., 1999) was used to construct 233 of the 291 Igl-2-3 residues of NCAM. CNS was used to carry out the final rounds of refinement. The final model contains the amino acids (-1) -238 and 241-289, and 266 water molecules. The amino acids were numbered according to the mature NCAM sequence. The Arg and Val residues originating from the clones site gave negative integers -2 and -1, respectively. Using all the reflections in the resolution range 50-2.0 A, the Rcristai is 21.8% and the Riüre is 23.8% (3% of the test set, which corresponds to 828 reflections). Table 1 shows the refinement and data collection statistics (Figure 1). The interdomain geometry was determined according to Bork et al. (1996), and buried accessible surface areas were calculated using the Protein-Protein Interaction Server (http://www.biochem.ucl.ac.uk/bsm/PP/server) (Jones and Thornton, 1996). The Figures were prepared with the programs MOLSCRIPT, RASTER3D (Kraulis, 1991, Merritt and Bacon, 1997), and Insight II (Accelrys). The atomic coordinates of the structure are shown in Table 2 (Figure 2). Protein Data Bank ID Code The coordinates of the structure have been deposited in Protein Data Bank under the code D 1QZ1. Cell Culture and Immunostaining The PC12-E2 cell line expressing defeocromocytoma (Wu and Bradshaw, 1995) was a gift from Dr. Klaus Seedorf, Hagedorn Research Institute, Denmark. Cells were cultured in Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 5% v / v fetal calf serum (FCS) and 10% v / v horse serum (HS), 100 U ml "1 of penicillin, 100 μg ml "1 streptomycin (all from Gibco BRL) at 37 ° C in a humidified atmosphere containing 5% C02. The line of fibroblastoid mouse cells, L929 (European Cell Culture Collection), was stably affected with the eukaryotic expression vector pHß-Apr-1-neo (Gunning et al., 1987) which contains the full-length cDNA encoding human 140-kDa NCAM or the vector alone. The NCAM cDNA does not contain the exons VASE, a, b, c, or AAG. The cells were routinely cultured at 37 ° C, 5% C02 in DMEM supplemented with 10% FCS v / v, 100 U ml "1 penicillin, and 100 μg ml" 1 streptomycin. For the analysis of neurite excrescence, PC12-E2 cells (8,000 cells per well) were seeded on top of a confluent monolayer of L929 transfected fibroblastoid cells in Tissue Culture Chamber Slides LabTek with four cavities (NUNC). The cells were cultured for 24 hours in DMEM supplemented with 1% v / v HS, before analysis. Cerebellar granule (CG?) Neurons were prepared from Wistar rats from postnatal day 3. Cerebellar tissue was dissected in modified Krebs-Ringer solution maintained on ice, and treated as described for anterior hippocampal neurons. All cell cultures were incubated at 37 ° C in a humidified atmosphere containing 5% C02. All animals were managed in accordance with national animal welfare guidelines. The primary cultures of CGN were plated at a density of 100, cells / cm2 in 8-well permanox slides coated with poly-L-lysine in Neurobasal-A medium (Gibco, BRL) supplemented with 2% (v / v) ) of B27, 0.5% (v / v) of glutamax, 100 U / ml of penicillin, 100 μg / ml of streptomycin and KCl, making the final concentration of KCl in the medium of 40 mM. 24 hours after plaque placement, cytosine-β-D-arabinofuranoside (Ara-C, Sigma-Aldrich) was added to a final concentration of 10 βM to prevent proliferation of the same cells, after which the neurons were left differentiate for six additional days at 37 ° C. The glycosylated recombinant rat Ig3 module of NCAM (wild-type and mutated forms) or the selected peptides were added immediately after seeding of the cells in order to evaluate their inhibitory effects on adhesion, as reflected by interference with neurite excrescence mediated by NCAM, Ig3wt, Ig3mutl, and Ig3mut2 were tested at a concentration of 500 μg ml. "1 Appropriate controls were included and the person performing the experiments does not know the identity of the mutants or peptides. of PC12-E2 cells, the co-cultures were fixed in paraformaldehyde at 4% v / v for 15 min.After washing in PBS, the cells were blocked with 10% v / v goat serum (DAKO) for 30 min. and subsequently incubated for 1 hour at room temperature with an anti-Thy-1 mouse monoclonal antibody (Caltag Laboratories) (1: 100 in PBS containing 10% v / v goat serum). the cells were incubated for 1 hour at room temperature with goat anti-mouse IgG Alexa-Fluor 568 ™ (Molecular Probest) (1: 1000 in PBS containing 10% goat serum). All washes were performed for 10 min in PBS, and they were repeated three times. To evaluate the length of the CGN neurites, the neurons were fixed after 24 hours in culture with 4% formaldehyde (v / v) for 20 minutes and subsequently immunostained using rabbit primary antibodies against GAP-43 and anti- body antibody. secondary face rabbit Alexa Fluor. Images of at least 200 neurons for each group in each individual experiment were obtained systematically using computer-aided fluorescence microscopy. The total length of neurites per cell was analyzed using the ProcessLength program (R0nn et al., 2000). Five independent experiments with the Ig3 module, its mutants, and the individual peptides were performed. In each experiment, neurites of 200-300 cells were analyzed. In order to compare the results of individual experiments and due to the inherently high variability of the cell experiments, the data were normalized by adjusting the difference between the average length of the neurites of PC12-E2 cells cultured in transfected and transfected NCAM-140 fibroblasts. with vector at 100%. Statistical evaluations were performed using a bilateral Student t test. Dynamic light scattering (DLS) measurements Measurements were made using an instrument DynaPro-MS / X (Protein Solutions) at 18 ° C. The deglycosylated preparations of Igl-2-3 (4 mg ml "1), Igl-2-3mut (4 mg ml" 1) and Ig3 (10 mg ml "1) in PBS pH 7.4 were used to determine the molecular weight of The recombinant proteins in solution Results and Analysis The X-ray structure of NCAM's Igl-2-3 modules The XAM Igl-2-3 X-ray structure of NCAM was determined at a resolution of 2.0 Á (see Table 1 Figure 1) In the structure of Igl-2-3, the Igl and Ig2 modules are placed in an extended conformation with Ig3 oriented at an angle of approximately 45 ° to the Igl-Ig2 axis (Figure 3). -Ig2 and between Ig2-Ig3 are short and comprise only two residues (Lys98-Leu99) and one residue (Asnl90), respectively.The complete structure of the Igl and Ig2 modules is very similar to the previously determined Igl-2 structure (Kasper et al., 2000) with deviations of mean square root (rmsd), of 0.7 (96 Ca atoms) and 0.8 Á (93 Ca atoms), respectively. ura Igl-2-3, the angle of inclination between Igl and Ig2 is 11 ° and differs in this way by 13 ° in comparison to the structure of Igl-2. The Ig3 module of 98 rat NCAM residues adopts the topology of an Igl module of the intermediate type II set (II) (Casasnovas et al., 1998). In the Ig3 module, the classic ß-sandwich consists of two ß-sheets with a total of nine ß-females (Figure 3B). The ß-strands A, B, D and E constitute one sheet and the ß-strands Al, C, C, F and G the second sheet. A cistern bridge Cys216-Cys269 connects the two ß-leaves. All strands are anti-parallel except strand A ', which runs parallel to the C-terminal part of strand G. Ig3 contains a site for N-linked glycosylation in Asn203 placed in the Ap strand. The EF loop (residues Lys261-Asp263) forms the a-helical turn 3? 0. The complete structure of rat Ig3 is similar to the structure of chicken Ig3 (Atkins et al., 2001) with r.m.s.s., of 1.65 A (95 Ca atoms). Parallel interactions between Ig modules Several characteristic interactions are observed in the structure of the Igl-2-3 fragment of NCAM that can be divided into two groups: Interactions where the long axes (N- to C-term) of two Igl-2- molecules 3 interactuantes are oriented in a parallel way and interactions where the long axes are oriented in an antiparallel way.

A parallel interaction and three main antiparallel interactions are observed in the crystal. The interaction of the parallel cross-type dimer of Igl-2-3 of NCAM comprises the Igl and Ig2 modules (Figure 5). The total buried surface area of this interface is 1594 A2 (per dimer), which is similar to what was observed previously in the cross-type dimers of Igl-2 (Kasper et al., 2000). The most prominent feature of the Igl-Ig2 interaction is the intercalation of two aromatic residues of Igl, Phe 19 and Tyr65, in hydrophobic cavities formed by Ig2 residues (Figure 5A), which was also observed in the Igl-2 structure. However, a narrower binding interface from Igl to Ig2 is observed in the Igl-2-3 structure, where the hydroxyl group of Tyr65 forms a direct hydrogen bond (H-bond) with Glul71, instead of an H- Water-mediated bond as seen in Igl-2. Tyr65 also makes three H-links to the side chains of Lysl33, Glul71, and Argl73. Argl73 forms part of the hydrophobic cavity of Ig2 and makes two H-bonds to Thr63. The parallel orientation of the side chains of Argl73 and Phel9 and the distance between the N atom of the guanidino group of Argl73 and the C atom? of the benzene ring of Phel9 (3.4 A) suggest a cation-p interaction between these two residues (Flocco and Mowbray, 1994). The Dynamic Light Dispersion (DLS) measurements showed that deglycosylated Igl-2-3 forms an individual species of molecules in solution with a molecular weight of approximately 78 kDa, which corresponds to a dimer. In order to demonstrate that the dimerization of Igl-2-3 was measured by the binding of Igl to Ig2 observed, an Igl-2-3 mutant (Igl-2-3mut) was produced containing three Ala substitutions: E11A, E16A, and K18A. These mutations have previously been shown to completely cancel out the dimerization of the NCAM fragment of IG1-2 in Jensen et al., 1999 solution). In the present structure Glull and Glul6 form intramolecular salt bridges, respectively, with Argl77 and Lys98 of the ligand region from Igl to Ig2 (not shown). These salt bridges probably contribute to the proper orientation of Igl with respect to Ig2 and therefore are important for the Igl to Ig2 interaction. Lysld forms an H-bond with the carboxyl group of Argl77 of the Ig2 modulus - which stabilizes the Igl-Ig2 interaction (Figure 5A). Lysl8 is located near Phel9, which is the critical residue for the Igl-Ig2 interaction as clearly demonstrated before (Atkins et al., 2001). Therefore, the interruption of the H-linkage of Lysl8-Argl77 may affect the orientation of Phel9 which leads to the elimination of the Igl-Ig2 interaction. The molecular weight of the Igl-2-3mut fragment was determined by DLS which is approximately 34 kDa, indicating a monomer. This confirms that the dimerization of Igl-2-3 is mediated by the binding of Igl to Ig2. Parallel (cis) interactions are not common among cell adhesion molecules. Thus, cis dimerization has been demonstrated for the cell adhesion molecules C-CAM1, C-CAM2, ICAM-1, nectin-2a, and JAM that correspond to the Ig superfamily (Hunter et al., 1996; Casasnovas et al., 1998; Miyahara et al., 2000; Kostrewa et al., 2001) as well as for N-, E-, and C-cadherins (Shapiro et al., 1995; Takeda et al., 1999; Brieher et al., 1996). It has been shown that the dimeric form of C-cadherin is capable of adhesion, while the monomeric form is not (Brieher et al., 1996). Anti-parallel interactions between Ig modules The anti-parallel interaction takes place between the Ig2 and Ig3 modules of two Igl-2-3 molecules, thus forming arrays of the Igl-2-3 dimers (Figure 4A, B). Ig2 from one molecule binds to Ig3 from a second molecule, and vice versa (Figure 3B). The residues included are 112-115, 143-146, and 158-161 of the B-strand, CD-asa / D-strand, and the E-strand of Ig2, and residues 200-205, 261, and 278- 289 of the A '-sheet, BF-asa, and G-strand of Ig3. A central element of this interaction is the intercalation of the Phe287 side chain of Ig3 in a hydrophobic cavity formed by the lateral chains of Vall45, Argl46, and Argl58 of the Ig2 and Lys285 Ig3 module. Argl58 is also involved in the binding of water-mediated hydrogen to residues Lys261 and Ala288, and Glyl59 makes an H-direct link to Asn203. The glass container leaves room for glycosylation in Asn203. In order to accommodate the N-linked glycosylation at this site, the side chain of ASN203 has to adopt another rotamer conformation. Thus, the carbohydrate will point away from the binding site and into a solvent channel in the crystal, and consequently Asn203 will not interfere with the Ig2-Ig3 interactions. An interaction between the two Ig3 modules is observed at the interface, since Glnl96 makes a water-mediated H-bond with Gln278. The total buried surface area of the Ig2 to Ig3 interface is 1407 A2 per dimer. According to Janin (1997), the probability of finding a non-specific interface from the size of the contact Ig2 to Ig3 is only 1.9%. Another anti-parallel interaction between two Igl-2-3 molecules is formed between two Ig2 modules (Figure 4C, D). This interaction comprises residues 103-121 and 150-158 of the AA '-ase / A' -hebra / A'B-asa and the DE-asa / E-strand and has the total buried surface area of 958 A2 per dimer ( Figure 4C). Here, the central residue appears to be Glull4, which makes two H-bonds to Serl51 (side chain and structure). Apart from an extensive hydrogen-binding network, especially through water molecules, Valll7, Valll9, Leul50, and Tyrl54 of both Ig2 modules form several hydrophobic contacts between 'si at the interface Ig2 to g2 (not shown). A slightly smaller anti-parallel interaction (858 A2 of the total buried surface per dimer) is formed between the Igl and Ig3 modules (Figure 4C, D), which comprises residues 32-47 and 76-88 of the C-strand / CC- handle / C -sheet / C'D-handle and F-strand / FG-asa / G-strand in Igl, and residues 198, 213-223, and 248-253 of the A-strand, B- strand / BC-loop, and D-strand / DE-loop in Ig3 (Figure 5D). Argl98 and Asp249 form H-direct bonds to the oxygen atoms of the structure of Aladl and Glu82 and two salt bridges with Lys76, respectively. Additionally, a water-mediated H-bond is formed between Lys42 and Asp250, one between Ser44 and Gly220, and two between Ser44 and Glu223. The conserved Phe36 and Phe221 are packaged against Asp249 and Gln47, respectively. Together two interaction sites Igl to Ig3 and a site of Ig2 to Ig2 constitute a predominant contact between the Igl-2-3 dimers in the crystal (2654 Á2) which forms the second arrangement of the Igl-2-3 dimers (Figure 4C, D) perpendicular to the arrangement mediated by Ig2 to Ig3 (Figure 2A, B). Contact areas of similar sizes have been found in other CAMs. The ICAM-1 Humama and JAM mouse cymithers have 1100 Á2 and 1200 Á2 of the total buried surface area (by dimer), respectively (Casasnovas et al., 1998; Kostrewa et al., 2001), whereas Trans-dimers of rat CD2 and axonin 1 of chicken / TAG-1 have even greater contact areas of 1300 Á2 2000 Á2 (Jones et al., 1992; Freigang et al., 2000). Ig3 Inhibits NCAM-dependent neurite excrescence It is known that the interaction of? CAM-? CAM induces neurite excrescence of PC12-E2 cells expressing? CAM cultured in a confluent monolayer of? CAM expressing fibroblasts (Kolkova et al., 2000 ). The inhibition of the interaction? CAM-NCAM will therefore inhibit the excitation of neurites in PC12-E2 cells. In order to examine the biological significance of the Igl to Ig3 and Ig2 to Ig3 contacts observed in the Igl-2-3 structure of? CAM, the inhibitory effect of the recombinant Ig3 modulus on adhesion was tested? CAM-? CAM. In addition, two Ig3 mutants were prepared which contain mutations of the residues R198A, D249G, E253A (Ig3mutl) from the contact site from Igl to Ig3 (see Figure 5D) and K285A, F287A (Ig3mut2) from the Ig2 to Ig3 contact site (see Figure 5B). In Figure 4, it can be seen that the wild type Ig3 module (Ig3wt) actually has an inhibitory effect, while both mutants are inactive, thereby strongly supporting both contact sites Igl to Ig3 and Ig2 to Ig3 are participants in the homophilic interactions. A similar co-culture test system of chicken retinal ganglion cells expressing NCAM cultured above mouse L cells transfected with NCAM-140 has been successfully used to demonstrate a mutation-disrupting effect at the homophilic binding site of the mouse. Ig3 module (IgG binding site to Ig3 in the present work) as well as to show an inhibition of neurite excrescence by synthetic peptides representing this homophilic binding site (Sandig et al., 1994). Interaction interface peptides inhibit neurite excrescence It has been shown previously that peptides that • represent homophilic binding sequences of Ig3 modules and NCAM Ig2 inhibit cell aggregation mediated by NCAM (Rao et al., 1992; Sandig et al., 1994; Rao et al., 1994; Soroka et al., 2002). Therefore, in order to further examine the biological significance of the contacts Igl to Ig2, Igl to Ig3, and Ig2 to Ig3 observed in the Igl-2-3 structure of NCAM, the inhibitory effect of a peptide serei was tested. which represent sequences of amino acids from the contact areas observed (Figure 6, 8-12). The Igl to Ig2 contact was represented by the peptide Pl-B (10-GEISVGESKFFL-21) (SEQ ID NO: 19) which covers the ß-strand B of Igl and which contains the key residue Phel9 at the Igl-Ig2 junction ( Kasper et al., 2000; Atkins et al., 2001). As a negative control, two peptides GEISVGESKAFL (Pl-B-F19A) (SEQ ID NO: 21) and GEISVGESKAAL (P1-B-F19A-F20A) (SEQ ID NO: 22) containing an individual Ala substitution of F19 and a Double substitution of Ala of both F19 and F20, respectively, were used. The Igl to Ig3 contact was represented by three peptides: AFSPNGEKLSPNQ (Pl-CD) (SEQ ID NO: 40), AKSWTAEDGTQSE (Pl-FG) (SEQ ID NO: 41) and KHIFSDDSSELTIRNVDKNDE (P3-DE) (SEQ ID NO: twenty) . The P3-DE peptide that covers the sequence of the ß-strands D and E and the EF loop of the Ig3 module is homologous to the sequence suggested above which is a homophilic binding site in the chicken NCAM Ig3 module (243-KYSFNYDGSELIIKKVDKSDE- 263) (SEQ ID NO: 23) (Rao et al., 1992). As a negative control, a truncated version of the peptide P3-DE 244-KHIFSDDSSE-253 (P3-DE-trunc) (SEQ ID NO: 24) was used. The P3-DE-trunc peptide is homologous to the chicken sequence 243-KYSFNYDGSE-252 (SEQ ID NO: 25) which was less potent than the longer sequence (Rao et al., 1992). The Ig2 to Ig2 contact was represented by the peptide P2-A'B (QEFKEGEDAVIV (SEQ ID NO: 17) The Ig2 to Ig3 contact was represented by the P2-CD (DVRRGIKKTD) peptides (SEQ ID NO: 42) and P2 -EF (QIRGIKKTD) (SEQ ID NO: 43) which covers the sequences of CD- and EF-ß-strands of the Ig2 module correspondingly, and P3-G (SIHLKVFAK) (SEQ ID NO: 13) of the Ig3 module. The sequence SIHLKVFAK (SEQ ID NO: 13) covers the C-terminal part of the ß-strand C that includes the Phe287 exposed to solvent. As negative controls, two peptides SIHLAVAAK (P3-G-K285AF287S) (SEQ ID NO: 26) and SIHLAVGAK (P3-G-K285A-F287G) (SEQ ID NO: 27) with substitutions of K285 and F287 were used. Both the peptides Pl-B and P3-G contain two hydrophobic residues (lie and Val / Leu) near their N-terms and at least one Phe residue near their C-terms. As a control, a peptide with similar hydrophobic properties was selected the peptide 213-TLVADADGFPEP-224 (P3-B) (SEQ ID NO: 3) which covers the β-strand B and the BC loop of the Ig3 module and which includes Gly220, Phe221, and Glu223 comprised in the Igl to Ig3 junction. Despite the similarity of the sequence with the peptides Pl-B and P3-G, the P3-B peptide was not active (Figure 6G). This is probably due to the fact that Phe221 in Ig3 partially exposed the solvent and that Gly220 and Glu223 form hydrogen bonds mediated by water (Figure 5D). By contrast, the peptides Pl-B, P3-DE, and P3-G either contain Phe buried in a hydrophobic cavity or residues that form direct H-bonds (Figure 5). The results of the biological test of the peptides are shown in Figures 4, 6-10. In co-cultures of PC12-E2 cells or CGN cells with fibroblasts expressing NCAM, peptides Pl-B, Pl-CD, P2-A'B, P3-DE, and P3 ~ G inhibited all neurite excrescence stimulated by NCAM, indicating a damaged NCAM-NCAM junction between the two cell layers. The corresponding control peptides have little or no inhibitory effect (Figure 6G). In contrast, the peptides P2-EF, P2-CD and P3-G do not affect the excitation of neurites stimulated by NCAM in co-cultures and are very capable stimulators of the excitation of neurites in primary cultures of individual CGN (Figures 8- 10). The peptides P2-A'B, and Pl-CD (Figures 8-12) were able to modulate the excitation of neurites mediated by homologous adhesion of NCAM, but did not stimulate the differentiation of individual CGN in primary culture. The peptide Pl-B interferes with the Igl-Ig2 interaction and thus inhibits the cis-dimerization mediated by Igl-Ig2 of NCAM. In the crystals of the Igl-2-3 module, rack-like arrangements of NCAM cis-dimers are observed, reflecting trans-NCAM interactions. The transinteractions thus seen require the quantization of NCAM molecules (Figure 4). The P3-DE and P3-G peptides do not affect cis-interactions that interfere with trans-interactions. Since the NCAM-dependent neurite excrescence depends on the NCAM-NCAM interactions between the two cell layers, an inhibition of these interactions will directly affect the NCAM-mediated neurite excrescence. In the present study, it was shown that mutations in peptides derived from the Ig3 module produce the same effect as that of similar mutations in the Ig3 module. This shows that in this experimental environment the peptides used mimic the Ig3 module, and thus can be used as a convenient and simple tool for further analysis. In addition, peptides representing the sequence of the homophilic binding site of the chicken NCAM Ig3 modulus (binding site Igl to Ig3 in the present work) have previously been used to identify and characterize the homophilic binding site of the Ig3 modulus (Rao). et al., 1992; Sandig et al., 1994; Rao et al., 1994). These results, combined with the Ig3 mutation studies, provide strong evidence of a biological role of the IgI to Ig2, IgI to Ig3, and Ig2 to Ig3 contacts observed. New zipper mechanism for homologous adhesion of NCAM The crystal structure of the Igl-2-3 fragment reveals new interactions between the Igl and Ig3 and Ig2 and Ig3 modules of NCAM, as well as shows IgG to Ig2 and Ig2 to Ig2 interactions previously observed ( Kasper et al., 2000). Together, these contacts mediate the formation of two perpendicular rack-type arrangements of the Igl-2-3 dimers (Figure 4). The parallel interaction of the Igl-2-3 molecules of NCAM in the crystal mediated by the contact gl to Ig2 can reflect an interaction between NCAM molecules present in the same cell surface, sis-interaction.

The anti-parallel interactions mediated by contacts Igl to Ig3, Ig2 to Ig2 and Ig2 to Ig3 can reflect the interaction of NCAM molecules present in opposite cells, trans-interactions. Based on all the observations presented, a homologous adhesion model of NCAM is proposed, consisting of two rack-type arrays of NCAM molecules (Figure 7). In the "compact" zipper (Figure 7A), NCAM cis-dimers originating from opposite cell membranes are arranged as arrays through interactions from Igl to Ig3 and Ig2 to Ig2. It is speculated that the "compact" zippers will probably form first since they allow greater distances between opposite cell membranes than the "flat" perpendicular zippers. In the "flat" zipper (Figure 7B), the Ig2 to Ig3 interactions suggest a lateral association between the "compact" zippers of NCAM thereby forming a double zipper adhesion complex (Figure 7C). The glycosylation at Asn203 of Ig3 (Figure 2) probably does not interfere with the ability to form the zippers as supported by the fact that the glycosylated Ig3 modulus inhibits CNS-mediated neurite excrescence, whereas glycosylated Ig3mut2 contains mutations in the Ig2-Ig3 binding site is inactive (Figure 6F, G). In the "compact" zipper, the heparin binding sites (133-KHKGRDVILKKDVRFI-148) (SEQ ID NO: 39) (Colé and Akeson, 1989) of the Igl-2-3 molecules are exposed to solvents (Figures 2C, D) and therefore accessible for binding to heparin and heparan sulfate molecules, suggesting that NCAM can be coupled in homophilic and heterophilic interactions simultaneously. In order to demonstrate the seven extracellular NCAM modules within a typical distance between plasma membranes of approximately 30 nm (Hall and Rutishauser, 1987), one turn has to be introduced into the NCAM molecules in the present model (Figure 7). NCAM analyzes by electron microscopy have revealed that a bent rod type structure (Hall and Rutishauser, 1987, Becker et al., 1989). The angle of the curve in the hinge region between the N-terminal (approximately 18 nm) and C-terminal (approximately 10 nm) parts varies considerably (50-140 °) with an average value of 98 ° (Becker et al., 1989) and presumably provides enough internal flexibility of? CAM to fit within the cell-cell distance. Based on these studies and on the average length of approximately 4.3 nm for a module Ig (present work) and approx 3.5 nm for a FnlII module (Leahy et al., 1996), the hinge region is most likely located after Ig4. An alignment of multiple sequences of the? CAM sequence of several vertebrate species reveals Pro, Lys, and Gly residues conserved in the PKLQGP sequence that connect the Ig4 and Ig5 modules. Since Pro and Gly are typically associated with polypeptide spins, this sequence will probably introduce a loop between the Ig4 and Ig5 modules. The double rack observed in the glass (Figure 7C) presents modules 1 to 3 of Ig at different heights, implying that the NCAM modules in the co-existence of the racks are turned or curved with different angles. This is in agreement with the electron microscopy data (Hall and Rutishauser, 1987, Becker et al., 1989). Although cis-interactions between Igl-Ig2 modules did not themselves measure cell-cell interactions, they probably contribute to the stability of trans interactions. This content is supported by the cell co-culture experiments using the peptide Pl-B which corresponds to the Igl site that binds to Ig2 (Figure 6).

In addition, an inhibitory effect on cellular aggregation was recently demonstrated for the peptide 172-GRILARGEI? FK-182 (peptide P2) (SEQ ID? O: 28) which represents the site in the Ig2 module that binds to the Igl module (Soroka et al., 2002). It is therefore suggested that the formation of cis-dimers may be a prerequisite for the establishment of trans-interactions. To our knowledge, only three X-ray structures of the adhesion molecules containing Ig modules have been determined to comprise three or more Ig modules (axonin-1 / TAGl (Freigang et al., 2000), hemolina (Su et al., 1998), and CD4 (Wu et al., 1997). An arrangement has been observed 'zipper-like type of trans-interaction cis-homodimers in the crystal structure of the binding adhesion molecule (JAM) (Kostrewa et al., 2001). A zipper mechanism of homophilic interactions was also suggested for axonin-1 / TAG-1 (Freigang et al., 2000), where the molecules provided alternately by opposite membranes form a linear rack type arrangement. However, the double rack formed by NCAM differs fundamentally from the zippers described above. In conclusion, a new model for NCAM homophilic union is presented, which is based on the formation of zippers. The model is in agreement with several studies that show that the Igl, Ig2 and Ig3 modules are all included in the homologous union of NCAM (Rao et al., 1992; Sandig et al., 1994; Kiselyov et al., 1997; Jensen et al., 1999; Kasper et al., 2000; Atkins et al., 2001) and reconciles a large body of biological data in conflict. The crystal structure of the Igl-2-3 fragment reveals details of two hitherto unknown interactions between Igl and Ig3 and between Ig2 and Ig3. Interestingly, the Igl and Ig2 modules of NCAM mediate both cis and trans interactions simultaneously, whereas Ig3 is comprised only in trans-interactions. Taken together, this study implies that it is the joined forces of the first three Ig modules that confers the adhesion resistance mediated by NCAM. It is noted that in relation to this date, the best method known by the applicant to carry out the present invention is that which is clear from the present description of the invention.

Claims (41)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. Crystal of a polypeptide comprising the Igl-2-3 module of NCAM, the polypeptide comprising amino acid residues 1 to 289 of SEQ ID NO. NO: 44, 'characterized in that the crystal comprises atoms arranged in a spatial relationship represented by the structure coordinates of Table 2 (Figure 2) or by the coordinates having a root mean square deviation thereof of no more than 2.5 TO.
2. 2. A crystal according to claim 1, characterized in that the polypeptide consists of amino acid residues 1 to 289 of SEQ ID NO: 44 and an additional sequence of amino acids of 1 to 4 ammonia residues.
3. 3. Crystal according to claim 1, characterized in that the crystal diffracts the X-rays for the determination of atomic coordinates at a resolution of at least 4 A.
4. 4. Glass according to claim 1, characterized in that the crystal differs in shape effective X-rays for the determination of atomic coordinates at a resolution as high as 5.0 Á. 5. Crystal according to claim 4 or 5, characterized in that the crystal effectively diffracts the X-rays for the determination of the atomic coordinates at a resolution of 1.5 Á. 6. Crystal according to claim 1, characterized in that the crystal has unit cell dimensions of a = 51.5 A, b = 108.
5. 5 A, c = 149.0 A, alpha = 90 °, beta = 90 °, gamma = 90 °. 7. A method characterized in that it is for selecting a candidate compound capable of modulating the differentiation, adhesion and / or survival of NCAM-presenting cells by modulating the interaction of i) the Igl module of an individual NCAM molecule with the Ig3 module of another molecule Individual NCAM, and / or ii) the Ig2 module of an individual NCAM molecule with the Ig3 module of another individual NCAM molecule, and / or iii) the ig2 module of an individual NCAM molecule with the Ig2 module of another individual NCAM molecule, the The method is characterized in that it comprises the steps of a) providing a crystalline polypeptide according to claim 1, b) generating a structural model of the NCAM Igl-2-3 module of (a) by using computer modeling techniques; c) evaluate in silicon compounds for the capacity of i) binding to the Igl module of NCAM in the homologous binding site of NCAM composed of the modules Igl, Ig2 and Ig3, and in this way mimic and / or modulate the interaction between the modules Igl and Ig3 from NCAM, where the modules are from two individual NCAM molecules, and / or ii) binding to the Ig3 module of NCAM at the homologous binding site of NCAM composed of the Igl, Ig2 and Ig3 modules, and mimic and / or modulate in this way the interaction between the Ig3 and IgG modules of NCAM, wherein the modules are of two individual NCAM molecules, and / or iii) binding to the IgAM module of NCAM at the homologous binding site of NCAM composed of the modules Igl, Ig2 and Ig3, and thus mimic the interaction between the modules Ig2 and Ig3 from NCAM, where the modules are of two molecules Individual NCAMs, and / or iv) binding to the Ig3 module of NCAM at the homologous binding site of NCAM composed of the Igl, Ig2 and Ig3 modules, and thus mimic and / or modulate the binding between the Ig3 and Ig2 modules of NCAM, where the modules are of two individual NCAM molecules, and / or v) binding to the NCAM Ig2 module at the homologous NCAM binding site composed of the Igl, Ig2 and Ig3 modules, and thus mimic and / or modulate the interaction between the Ig2 and Ig2 modules of NCAM, where the modules are from two individual NCAM molecules, by using the structural model of the Igl-2-3 module of? CAM of (b); d) selecting a candidate compound capable of at least one interaction of (c), or e) testing the candidate compound of (d) in an in vitro assay for the ability to modulate differentiation, adhesion and / or survival of cells displaying NCAM, assays comprising at least one molecule presenting? CAM, and / of) testing the candidate compound of (d) in an assay comprising evaluating the ability of the compound of at least one interaction of (b) upon contacting the - composed of at least one individual fragment of a CAM molecule, the fragment comprising a sequence of consecutive residues of ammonia corresponding to the sequence of the Igl-2-3 module of? CAM comprising residues 1 to 289 of the sequence set forth in SEQ ID? O: 44. 8. Compound capable of binding to the homophilic binding site of? CAM composed of the Igl, Ig2 and Ig3 modules, characterized in that the compound is capable of i) binding to the Igl module of? CAM in the homophilic binding site of? CAM, and in this way mimic and / or modulate the interaction between the Igl and Ig3 modules of? CAM, where the modules are of two individual NCAM molecules of opposite contact cells, and / or ii) binding to the Ig3 module of NCAM at the site of homologous NCAM binding, and thereby mimic and / or modulate the interaction between the Ig3 and IgG modules of NCAM, where the modules are from two individual NCAM molecules of opposite contact cells, and / or iii) binding to the Ig2 module of NCAM at the homologous binding site of NCAM, and thereby mimic the interaction between the IgM and Ig3 modules of NCAM, where the modules are from two individual NCAM molecules of opposite contact cells, and / or iv) binding to NCAM Ig3 module at the homologous NCAM binding site, and thereby mimic and / or modulate the binding between the NCAM Ig3 and Ig2 modules, wherein the modules are from two individual NCAM molecules of opposite contact cells, and / ov) binding to the NCAM Ig2 module at the homologous binding site of NCAM, and thereby mimic and / or modulate the interaction between the IgAM and Ig2 modules of NCAM, wherein the modules are from two individual NCAM molecules of cells opposite of contact, the compound that is a peptide sequence identified as SEQ ID NO: 1, 2, 3, 4, 7, 10, 11, 12, 13, 14, 16, 17, 18, 40 or 41, or that is a fragment or variant of the sequence, wherein the sequence The peptide is selected by the method according to claim 20. Compound according to claim 8, characterized in that it has the amino acid sequence WFSPNGEKLSPNQ (SEQ ID? O: 1). 10. Compound according to claim 8. , characterized in that it has the amino acid sequence YKCWTAEDGTQSE (SEQ ID? O: 2) 11. Compound according to claim 8, characterized in that it has the sequence of amino acids. TLVADADGFPEP (SEQ ID? O: 3). 12. Compound according to claim 8, characterized in that it has the amino acid sequence QIRGIKKTD (SEQ ID? O: 4). 13. Compound in accordance with the claim 8, characterized in that it has the amino acid sequence DVR (SEQ ID? O: 5). 14. Compound according to claim 8, characterized in that it has the amino acid sequence RGIKKTD (SEQ ID? O: 6). 15. Compound according to claim 8, characterized in that it has the amino acid sequence DVRRGIKKTD (SEQ ID? O: 7). 16. Compound according to claim 8, characterized in that it has the amino acid sequence KEGED (SEQ ID NO: 8). 17. Compound in accordance with the claim 8, characterized in that it has the amino acid sequence IRGIKKTD (SEQ ID NO: 9). 18. Compound in accordance with the claim 8, characterized in that it has the amino acid sequence KEGEDGIRGIKKTD (SEQ ID NO: 10). 19. Compound according to claim 8, characterized in that it has the amino acid sequence DKNDE (SEQ ID? O: 11). 20. Compound according to claim 8, characterized in that it has the amino acid sequence TVQARNSIVNAT (SEQ ID? O: 12). 21. Compound according to claim 8, characterized in that it has the amino acid sequence SIHLKVFAK (SEQ ID? O: 13). 22. Compound according to claim 8, characterized in that it has the amino acid sequence LS? YLQIR (SEQ ID? O: 14). 23. Compound in accordance with the claim 8, characterized in that it has the amino acid sequence RFIVLS ?? YLQI (SEQ ID? O: 15). 24. Compound in accordance with the claim 8, characterized in that it has the amino acid sequence KKDVRFIVLS? NYLQI (SEQ ID? O: 16) 25. Compound according to claim 8, characterized in that it has the amino acid sequence QEFKEGEDAVIV (SEQ ID NO: 17). 26. Compound according to claim 8, characterized in that it has the amino acid sequence KEGEDAVIVCD (SEQ ID NO: 18). 27. Compound according to claim 8, characterized in that it has the amino acid sequence AFSPNGEKLSPNQ (SEQ ID NO: 40). 28. Compound in accordance with the claim 8, characterized in that it has the amino acid sequence AKSWTAEDGTQSE (SEQ ID NO: 41). 29. Use of one or more compounds according to any of claims 8-28 for the manufacture of a medicament for the treatment of a disease wherein modulation of cell differentiation, adhesion and / or survival is essential for the treatment. presenting NCAM. 30. Use according to claim 29, wherein the medicament is for treating cells that present NCAM normal, degenerate or damaged. 31. Use according to claim 29, wherein the medicament is for treatment comprising the stimulation of differentiation and / or survival of cells displaying? CAM. 32. Use according to claim 29, wherein the medicament is for treating diseases and conditions of the central and peripheral nervous system, or of the muscles or of various organs. 33. Use according to claim 29, wherein the medicament is for treating diseases or conditions of the central and peripheral nervous system., such as post-operative damage of nerves, traumatic nerve damage, damaged myelination of nerve fibers, post-hischemic damage, for example resulting from an attack, Parkinson's disease, Alzheimer's disease, Huntington's disease, dementias, such as multi-infarct dementia, sclerosis, nerve degeneration associated with diabetes mellitus, disorders affecting the circadian clock or neuro-muscular transmission, and schizophrenia, mood disorders, such as manic depression; for the treatment of diseases or conditions of the muscles including conditions of damaged confution of neuromuscular connections, such as after organ transplantation, or such as traumatic or genetic atrophic muscle disorders; or for the treatment of diseases or conditions of various organs, such as degenerative condition of the gonads, the pancreas such as diabetes mellitus type I and II, of the kidney such as nephrosis and of the heart, liver and intestine. 34. Use according to claim 29, wherein the medicament is for the treatment of post-operative nerve damage, traumatic nerve damage, damaged myelination of nerve fibers, post-hischemic damage, for example resulting from stroke, Parkinson's disease, Alzheimer's disease, dementias such as multi-infarct dementia, sclerosis, nerve degeneration associated with diabetes mellitus, disorders affecting the circadian clock • or neuro-muscular transmission, and schizophrenia, mood disorders, such as manic depression. 35. Use according to claim 29, wherein the medicament is for promoting wound healing. 36. Use according to claim 29, wherein the medicament is for the treatment of cancer. 37. Use according to claim 29, wherein the medicament is for preventing cell death of heart muscle cells, such as after acute myocardial infarction, or after angiogenesis. 38. Use according to claim 29, wherein the medicament is for promoting revascularization. 39. Use according to claim 29, wherein the medicament is for stimulating the ability to learn and / or memory in the short and / or long term. 40. Use of a crystal of the Igl-2-3 module of NCAM according to claims 1-6 for the detection in silicon of a candidate compound capable of modulating cell differentiation and / or survival, neural plasticity dependent on homologous adhesion of NCAM. 41. Pharmaceutical composition, characterized in that it comprises one or more compounds according to any of claims 8-28.