WO2005119525A1

WO2005119525A1 - 11βHSD1 CRYSTAL STRUCTURES FOR STRUCTURE BASED DRUG DESIGN

Info

Publication number: WO2005119525A1
Application number: PCT/IB2005/001463
Authority: WO
Inventors: Arturo Antonio Castro; Yuan-Hua Ding; Jacques Ermolieff; Jason Darryl Hughes; Christine Loh Janosky; Darcy John Reinard Kohls; Chee Meng Low; Barbara Mroczkowski; Thomas Adelbert Pauly; Paul Abraham Rejto; Yan Zhang; Jeff Xianchao Zhu
Original assignee: Pfizer Products Inc.
Priority date: 2004-06-04
Filing date: 2005-05-23
Publication date: 2005-12-15

Abstract

Crystalline compositions of 11 β Hydroxysteroid dehydrogenase (11βHSD1), and the nucleotide and amino acid sequences utilized to form such crystalline compositions. The crystalline compositions then used to screen 11βHSD1 ligands. The ligands are formulated into pharmaceutical compositions, and used for treatment of disease states or disorders mediated by 11βHSD1.

Description

11jSHSD1 CRYSTAL STRUCTURES FOR STRUCTURE BASED DRUG DESIGN Field of Invention The present invention relates to crystalline compositions of mammalian 11 ?-Hydroxysteroid Dehydrogenase Type 1 (hereafter 11^HSD1 ); nucleotide sequences and amino acid sequences utilized to form said crystalline compositions; and methods of determining the 3 dimensional (hereafter 3-D) X-ray atomic coordinates of the formed crystals. The invention is further directed to methods of identifying ligands of 11 HSD1 to a binding site using structure based drug design and to the use of such ligands as inhibitors for treatment of disease states or disorders mediated by 11 ?HSD1. Background 11/?HSD1 is an NADPH-dependent short-chain oxidoreductase (SCOR) that catalyzes the conversion of glucocorticoid cortisone to cortisol. 11 ?HSD1 amplifies the local concentration of cortisol in select tissues (e.g. liver, adipose) and thereby modulates glucocorticoid receptor signaling. Increasing evidence in the literature implicates 11^HSD1 in metabolic syndrome. For example, 11βHSD1 homozygous knockout mice resist hyperglycemia induced by a high fat diet (Kotelevtsev et al., PNAS, 94:14294-14929 (1997)). Conversely, transgenic mice overexpressing 11 ?HSD1 in adipose tissue develop diabetes, visceral obesity, and hyperlipidemia (Mazusaki, et al., Science, 294:2166-2170 (2001)). Transgenic mice overexpressing 11/?HSD1 in liver develop dyslipidemia and hypertension (Paterson et al., PNAS, 101 :7088- 7093 (2004)). A summary of the SCOR family of which 11 ?HSD1 is a member, has been published by Duax et al., Proteins, 53:931-943 (2003). 11jøHSHD has been shown to be inhibited by glycyrrletinic acid (Stewart, P.M., Lancet, 2:821-823 (1987); and Monder, C. et al., Endocrinology, 125:1046-1053 (1989)) Duax et al. have discussed their efforts to crystallize 11 ?HSD1 (personal communication). Additional crystallization studies on human and guinea pig 11 ?HSD1 have been reported by Hosfield et al. JBC Papers in Press, October 28, 2004, Manuscript M41104200 and Ogg et al., JBC Papers in Press, November 12, 2004, Manuscript M412463200. The use, design and synthesis of various 11/7HSD1 inhibitors have been reported in the periodical and patent literature. See, for example, Zhang et al.,

J. Steroid Biochem Mol. Bio., 49:81-85 (1994); Sampath-Kumar et al., J. Steroid Biochem Mol. Biol., 62:195- 199 (1997) and WO 04/103980 A1 among others. Summary of the Invention The present invention relates generally to crystalline compositions of 11 JHSD1 , and specifically including at least one truncated form and to various constructs of 11 7HSD1 ; and to nucleic acid sequences, encoding amino acid sequences utilized for preparing said crystalline compositions. The 11 ?HSD1 crystalline composition includes at least two 11/?HSD1 polypeptides and which form at least one dimer. Preferably the crystalline composition includes three 11 ?HSD1 polypeptides. The invention further relates to methods of determining the 3-D X-ray atomic coordinates of the formed crystals and methods of using said atomic coordinates in conjunction with computational methods in structure based drug design. The crystalline compositions of the present invention are utilized for screening and identifying inhibitors of 11 SHSD1. The inhibitors or chemical compounds so identified are specific to a 11βHSD1 binding site and could be utilized as pharmaceutical compositions for treatment of diseases or disorders mediated by 11βHSD1 including therapeutic interventions for example, to metabolic disorders, diabetes, obesity, ophthalmology, impaired cognition, osteofrailty, and cell differentiation. In one embodiment the invention is directed to crystalline composition of a truncated form of mammalian 1 1 ?HSD1 incorporating a substrate binding site or binding domain. In another embodiment the invention provides a crystalline composition of a truncated form of human 11 ?HSD1 and which optimally includes at least one amino acid substitution in the substrate binding domain. In the above embodiments, the invention further comprises methods of refining and evaluating full or partial 3-D coordinates. This method may thus be used to generate 3-D structures for proteins for ¹ / which 3-D atomic coordinates have not been determined. Depending on the extent of sequence homology, the newly generated structures may help to elucidate enzymatic mechanisms, or be used in conjunction with other molecular modeling techniques in structure based drug design. In another aspect, the present invention provides a method for identifying inhibitors, ligands, and the like of 11 ?HSD1 by providing the coordinates of molecule(s) of 11 ?HSD1 for a computerized modeling system; identifying chemical entities that are likely to bind to or interfere with the molecule(s), e.g., by screening a small molecule library; and, optionally, procuring or synthesizing and assaying the compositions, compounds or analogues derived therefrom for bioactivity. In further embodiments, the information obtained by the above method is used to iteratively refine or modify the structure of the original ligand. Thus, once a ligand is found to modulate the activity of said enzyme, the structural aspects of the ligand may be modified to generate a structural analog of the ligand. This analog can then be used in the above method to identify additional ligands. One of ordinary skill in the art will know the various ways a structure may be modified. In other embodiments of the present invention, the identified ligand(s) is a selective inhibitor of 110HSD1. Thus, in a first aspect, the present invention relates to 11 ?HSD1 crystalline compositions, including at least one mammalian 11 ?HSD1 polypeptide including a substrate binding domain. As a specific aspect the 11 ?HSD1 crystaline coordinates of a guinea pig polypeptide (Form 1) N24- E293 is provided. The crystal composition has a unit cell: a=171.080 A, b=62.831 A, c=89.646 A, a=β=γ=90.0° in space group P21212 and which effectively diffracts X-rays beyond 2.1 A for determination of the atomic coordinates of the guinea pig 11 ?HSD1 polypeptide to a resolution range of about 2.14-2.07 A resolution. As a further aspect a second set of 11 JHSD1 crystaline coordinates for a guinea pig polypeptide (Form 2) N24-A300 is provided. As a still further aspect the 11βHSD1 crystaline coordinates of human polypeptide is provided. In a second aspect, the present invention relates to crystals of an 11 ?HSD1 and ligand complex. In a third aspect, the present invention relates to polypeptides comprising the 11 ?HSD1 amino acid sequence as set forth in GenBank Accession No. AF188005, particularly N24 to E293, or N24-A300 or a homologue, functional fragment, e.g. a truncated fragment, variant, or analogue thereof. Additional species specific polypeptides are provided in GenBank Accession Nos. M76665(human); X83202 and S75207 (mouse); JO5107 (rat); Q7M3I4 (rabbit); X69561 (sheep); AF414124 (pig) and S63400 (squirrel) or variants thereof. A truncated fragment of these species specific polypeptides are preferably utilized for crystallography studies. In a fourth aspect, the present invention relates to polypeptides consisting essentially of 11 ?HSD1 as provided in SEQ ID NO: 7 or SEQ ID NO: 8 or SEQ ID NO: 9 or SEQ ID NO: 15 or SEQ ID NO: 25 and to nucleic acid sequences encoding said polypeptides. In a fifth aspect, the present invention relates to computers for producing a three-dimensional representation of a polypeptide with a 11/JHSD1 amino acid sequence particularly spanning amino acids beginning at the 24th amino acid of the N-terminal end to the C-terminal end, i.e., the 11 ?HSD1 lower case amino acid residues; of SEQ ID NO: 7; of SEQ ID NO: 8; of SEQ ID NO: 9; of SEQ ID NO: 15 ; or of SEQ ID NO: 25, or a homologue, functional fragment, variant, or analogue thereof. The numbering of the guinea pig 11 ?HSD1 amino acids described herein utilize the numbering convention provided by Pu and Yang,

Steroids, 65:148-156(2000). In the guinea pig nucleotide sequence utilized herein two substitutions are noted from the published sequence C355T and T611 C which respectively result in A103V and a silent mutation with no change in the amino acid residue. The numbering of the human 11 HSD1 amino acids described herein corresponds to the numbering convention provided by Tannin et al., J. Biol. Chem., 266:16653-16658 (1991). The human 11 HSD1 sequences preferably utilized herein incorporate at least one amino acid substitution, e.g. F278E; L262R and F278E; or M179L, L262R, F278E and M286W. Additional substitutions may be provided as discussed below. The three dimensional representation is optimally utilized in structural analysis with a computer- readable data storage medium comprising a data storage material encoded with computer-readable data, where said data comprises the structure coordinates of FIG. 6, FIG. 9 or FIG. 10 or portions thereof, a working memory for storing instructions for processing said computer-readable data, a central-processing unit coupled to said working memory and to said computer-readable data storage medium for processing said computer-machine readable data into said three-dimensional representation, and a display coupled to said central-processing unit for displaying said representation. In a sixth aspect, the present invention relates to computers for producing a three-dimensional representation of a molecule or molecular complex comprising the atomic coordinates of one of FIG. 6, FIG. 9 or FIG 10 comprising a computer-readable data storage medium comprising a data storage material encoded with computer-readable data, wherein said data comprises the structure coordinates of one of FIG. 6, FIG. 9 or FIG. 10 or portions thereof working memory for storing instructions for processing said computer-readable data, a central-processing unit coupled to said working memory and to said computer- readable data storage medium for processing said computer-machine readable data into said three- dimensional representation, and a display coupled to said central-processing unit for displaying said representation. In a seventh aspect, the present invention relates to computers for producing a 3-D representation of a molecule or molecular complex comprising the atomic coordinates having a root mean square deviation of less than 2.0, 1.7, 1.5, 1.2, 1.0, 0.7, 0.5, or 0.2 A from the atomic coordinates for the carbon backbone atoms listed in one of FIG. 6, FIG. 9 or FIG. 10 comprising a computer-readable data storage medium comprising a data storage material encoded with computer-readable data, wherein said data comprises the structure coordinates of one of FIG. 6, FIG. 9 or FIG. 10 or portions thereof, a working memory for storing instructions for processing said computer-readable data, a central-processing unit coupled to said working memory and to said computer-readable data storage medium for processing said computer-machine readable data into said three-dimensional representation, and a display coupled to said central-processing unit for displaying said representation. In an eighth aspect, the present invention relates to computers for producing a 3-D representation of a molecule or molecular complex comprising a specific binding site defined by the structure coordinates in one of FIG. 6, FIG. 9 or FIG. 10 or the structural coordinates of a portion of the residues in one of FIG. 6, FIG. 9, or FIG. 10, comprising at least one residue, preferably at least five residues and more preferably at least fifteen residues, or the structural coordinates of one or more 11 ?HSD1 amino acids sequences as set forth in the GenBank deposits noted above, wherein said computer comprises a computer-readable data storage medium comprising a data storage material encoded with computer-readable data, wherein said data comprises in the case of guinea pig the structure coordinates of FIG. 6, or portions thereof, a working memory for storing instructions for processing said computer-readable data, a central-processing unit coupled to said working memory and to said computer-readable data storage medium for processing said computer-machine readable data into said three-dimensional representation, and a display coupled to said central-processing unit for displaying said representation. In a ninth aspect, the present invention relates to methods for generating the 3-D atomic coordinates of protein homologues of 1 IβHSDI using the X-ray coordinates of 11 ?HSD1 shown in one of FIG. 6, FIG. 9 or FIG. 10 said methods comprising identifying the sequences of one or more proteins which are homologues of 11 ?HSD1 , aligning the homologue sequences with the sequence of 11/JHSD1 , identifying structurally conserved and structurally variable regions between the homologue sequences, and 11 ?HSD1 , generating 3-D coordinates for structurally conserved residues, variable regions and side-chains of the homologue sequences from those of 11 ?HSD1 , and combining the 3-D coordinates of the conserved residues, variable regions and side-chain conformations to generate full or partial 3-D coordinates for said homologue sequences. In a tenth aspect, the present invention relates to methods for identifying potential ligands for 11jffHSD1 or homologues, analogues or variants thereof, comprising the steps of displaying three dimensional structure of 11 ?HSD1 enzyme, or portions thereof, as defined by atomic coordinates in one of FIG. 6, FIG. 9 or FIG. 10 on a computer display screen, optionally replacing one or more 11βHSD1 amino acid residues listed in SEQ ID NO:7; SEQ ID NO:8; SEQ ID NO: 9; SEQ ID, NO: 15 or SEQ ID NO: 25 or amino acids of the GenBank deposits noted above, or one or more of the amino acids listed in Tables 2-4, or one or more amino acid residues selected from S170, Y177, Y183 and/or T227 and particularly to S170 and/or Y183 in said three-dimensional structure, for example, with a different naturally occurring amino acid or an unnatural amino acid, employing said three-dimensional structure to design or select said ligand, contacting said ligand with 11 ?HSD1 , or variant thereof, in the presence of one or more substrates, and measuring the ability of said ligand to modulate the activity of 11 ?HSD1. One such amino acid substitution for the human 11 HSD1 is F278E. Additional amino acid substitutions may include: M179L; L262R and M286W. The substitution of one or more amino acids or combined amino acid substitutions may improve the solubility stability and activity properties of the polypeptide. Brief Description of the Drawings

FIG. 1 is an orthogonal view of the three polypeptide chains of guinea pig 11 ?HSD1 observed in the asymmetry unit in the current crystal form. The polypeptide chains are in ribbon representation. Bound NADP+ is shown as a ball model. Polypeptide chain A forms a dimer with chain C. Polypeptide chain B forms a similar dimer with a symmetry related molecule. FIG. 2 is an orthogonal view of the dimeric structure of guinea pig 11/JHSD1 (chain A and Chain C in FIG. 1). The position of the two-fold axis is shown. The polypeptide chains are in ribbon representation. Bound NADP+ is shown as a sticks model. Cortisol (shown as a ball model) was modeled in to indicate active sites.

FIG. 3 is another orthogonal view (along the 2-fold axis) of the dimeric structure of guinea pig 11 ?HSD1 (as in FIG. 2).

FIG. 4 is an orthogonal view of chain C and its active site. Locations of secondary structures (Table 2) are marked. The active site of chain C also contains to last helix from chain A (marked as σG'2).

FIG. 5 is another orthogonal view of chain C and its active site.

FIG. 6 lists the coordinates for the apo structure of guinea pig 11jffHSD1, (Form 1) of SEQ ID NO: 7. FIG. 7 is the same orthogonal view of the dimeric structure of guinea pig 11 JHSD1 as shown in FIG. 2. The two thick dotted lines depict the lipid bilayer of a membrane. The proposed C-terminal membrane association region (helices G1 and G2 in both chain A and Chain C, see Table 2) is indicated by the oval. This orientation to the membrane permits the N-terminus of each monomer to be positioned for transmembrane helix formation. The entrance to the cortisol/contisone binding-pocket is located close to the membrane. This allows the water-insoluble cortisone/cortisol quickly diffuse into and out of the active site from the membrane.

FIG. 8 is an alignment of the C-terminus region of 11/?HSD1 across different species. It indicates that key residues involved in membrane binding are relatively conserved and thus is a common feature in these species. FIG. 9 lists a second set of coordinates for the apo structure of guinea pig 11 HSD1 (Form 2) of SEQ ID NO: 8.

FIG. 10 lists the coordinates for the apo structure of human 11βHSD1 of SEQ ID NO 15. FIG. 11 lists the coordinates of the co-complex of guinea pig 11/?HSD1 of SEQ ID NO: 8 and 18/? glycyrrhetinic acid.

FIG. 12 is an orthogonal view of the co-complex of guinea pig 11 JHSD1 and 18/? glycyrrhetinic acid. Detailed Description of the Invention The present invention relates to 3-D crystalline compositions of 11 ?HSD1 , X-ray atomic coordinates of said crystalline compositions, and methods of using said atomic coordinates in conjunction with computational methods to identify a binding site used to identify ligands which interact with said binding site to inhibit 11 ?HSD1. For convenience, certain terms employed in the specification, examples, and appendant claims are collected here. In the specification and appendant claims the singular form includes plural forms unless the context dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All patents, patent applications and periodical references cited in the specification are incorporated by reference herein. The term "affinity" as used herein refers to the tendency of a molecule to associate with another.

The affinity of a drug is its ability to bind to its biological target (receptor, enzyme, transport system, etc.) For pharmacological receptors, affinity can be thought of as the frequency with which the drug, when brought into the proximity of a receptor by diffusion, will reside at a position of minimum free energy within the force field of that receptor. The term "analog" or "analogue" as used herein refers to a drug or chemical compound whose structure is related in some way to that of another drug or chemical compound, but whose chemical and biological properties may be, quite different. As used herein the term "binding site" refers to a specific region or atom(s) in a molecular entity that is capable of entering into a stabilizing interaction with another molecular entity. In embodiments the term also refers to the reactive parts of a macromolecule that directly participate in its specific combination with another molecule. In certain other embodiments, a binding site may be comprised or defined by the three dimensional arrangement of one or more amino acid residues within a folded polypeptide. In embodiments, the binding site further comprises prosthetic groups, water molecules or metal ions which may interact with one or more amino acid residues. Prosthetic groups, water molecules, or metal ions may be apparent from X-ray crystallographic data, or may be added to an apoprotein or enzyme using in silico methods. "To clone" as used herein, as will be apparent to skilled artisan, is meant to obtain exact copies of a given polynucleotide molecule using recombinant DNA technology. Furthermore, "to clone into" is meant to insert a given first polynucleotide sequence into a second polynucleotide sequence, preferably such that a functional unit combining the functions of the first and the second polynucleotides results, for example, without limitation, a polynucleotide from which a fusion protein may be translationally provided, which fusion protein comprises amino acid sequences encoded by the first and the second polynucleotide sequences. Details of molecular cloning can be found in a number of commonly used laboratory protocol books such as Molecular Cloning: A Laboratory Manual, 2nd Ed., ed. by Sambrook, Fritsch and Maniatis (Cold Spring Harbor Laboratory Press (1989)). The term "co-crystallization" as used herein is taken to mean crystallization of a protein/ligand complex. The term "complex" or "co-complex" are used interchangeably and refer to an 11 JHSD1 molecule or crystal, or a variant, or homologue of 11 ?HSD1 in covalent or non-covalent association with a substrate, or ligand. The term "contacting" as used herein applies to in silico, in vitro, or in vivo experiments. i As used herein, the terms "gene", "recombinant gene" and "gene construct" refer to a nucleic acid comprising an open reading frame encoding a polypeptide, including both exon and (optionally) intron sequences. The term "intron" refers to a DNA sequence present in a given gene which is not translated into protein and is generally found between exons. The term "high affinity" as used herein means strong binding affinity between molecules with a dissociation constant K_D of no greater than 1 μM. In a preferred case, the K is less than 100 nM, 10 nM, 1 nM, 100 pM, or even 10 pM or less. In a most preferred embodiment, the two molecules can be covalently linked (K_D is essentially 0). The term "homologue" or "homolog" as used herein refers to polypeptides having greater than 50%, amino acid sequence identity with 11βHSD1 enzyme as described in SEQ ID NO: 7 or SEQ ID NO: 8 or SEQ ID NO: 9 or SEQ ID NO: 15 or SEQ ID NO: 25 or the GenBank deposits above, or any substrate binding domain described herein. SEQ ID NO: 7 is a partial amino acid sequence of the guinea pig 11/?HSD1. SEQ ID NO: 8 is a truncated amino acid sequence of guinea pig 11 JHSD1 that was cocrystallized in the Examples below. SEQ ID NO: 15 is a mutated sequence of human 11/?HSD1 that was crystallized. SEQ ID NO: 25 is another mutated sequence of human 11 ?HSD1 that was also crystallized (data not shown). Those of skill in the art understand that a set of structure coordinates determined by X-ray crystallography is not without standard error. The term "substantially similar atomic coordinates" or atomic coordinates that are "substantially similar" refers to any set of structure coordinates of 11βHSD1 provided herein or 11βHSD1 homologues, or 11jffHSD1 variants, polypeptide fragments, described by atomic coordinates that have a root mean square deviation for the atomic coordinates of protein backbone atoms (N, Ca, C, and O) of less than about 2.5, 2.0, 1.7, 1.5, 1.2, 1.0, 0.7, 0.5, or even 0.2 A when superimposed- using backbone atoms- of structure coordinates listed in one of FIG. 6, FIG. 9 or FIG. 10. The term "substantially similar" also applies an assembly of amino acid residues that may or may not form a contiguous polypeptide chain, but whose three dimensional arrangement of atomic coordinates have a root mean square deviation for the atomic coordinates of protein backbone atoms (N, Ca, C, and O), or the side chain atoms, of less than about 2.5, 2.0, 1.7, 1.5, 1.2, 1.0, 0.7, 0.5, or even 0.2 A when superimposed- using backbone atoms, or the side chain atoms of the atomic coordinates of similar or the same amino acids from the coordinates listed in one of FIG. 6, FIG. 9 or FIG. 10 or FIG. 11. To clarify further, but not intending to be limiting, an example of an assembly of amino acids may be the amino acid residues that form a binding site in an enzyme. These residues may have one or more intervening residues which are distant from the binding site, and therefore may minimally interact with a ligand in the binding sites. In such occurrences, the binding site may be defined for the purpose of structure based drug design as comprising at least three amino acid residues provided in Table 2 or Table 3 or selected amino acids of Table 2 or Table 3. For example in the case of guinea pig 11/ΪHSD1 , amino acid residues V121 or (1121 in human) to Y284 of Table 2 are known to be near or at the binding site. Thus any molecular assembly that has a root mean square deviation from the atomic coordinates of the protein backbone atoms (N, Ca, C, and O), or the side chain atoms, of one or more of V121 to Y284 as provided in SEQ ID NO:7, or SEQ ID NO:8 (note 1121 for human) or SEQ ID NO: 9 or SEQ ID NO: 15 or SEQ ID NO: 25 any conservative substitutions thereof, of less than about 2.5, 2.0, 1.7, 1.5, 1.2, 1.0, 0.7, 0.5, or even 0.2 A when superimposed will be considered substantially similar to the coordinates listed in one of FIG. 6, FIG. 9 or FIG. 10.

"Substantially similar" atomic coordinates, for the purposes of this invention are considered identical to the coordinates, or portions thereof, listed in one of FIG. 6, FIG. 9 or FIG. 10. Those skilled in the art further understand that the coordinates listed in one of FIG. 6, FIG. 9 or FIG. 10 or FIG. 11 or portions thereof may be transformed into a different set of coordinates using various mathematical algorithms without departing from the present invention. For example, the coordinates listed in one of FIG. 6, FIG. 9 or FIG. 10 or FIG. 11 , or portions thereof, may be transformed by algorithms, which translate or rotate the atomic coordinates. Alternatively, molecular mechanics, molecular dynamics or ab initio algorithms may modify the atomic coordinates. Atomic coordinates generated from the coordinates listed in one of FIG. 6, FIG. 9 or FIG. 10 or FIG. 1 1 or portions thereof, using any of the aforementioned algorithms shall be considered identical to the coordinates listed in FIG. 6 or FIG. 9 or FIG. 10 or FIG. 11 respectively. The term "in silico" as used herein refers to experiments carried out using computer simulations. In embodiments, the in silico methods are molecular modeling methods wherein 3-dimensional (3-D) models of macromolecules or ligands are generated. In other embodiments, the in silico methods comprise computationally assessing ligand binding interactions. The term "modulate" as used herein refers to both upregulation (i.e., activation or stimulation, e.g., by agonizing or potentiating) and down-regulation (i.e., inhibition or suppression, e.g., by antagonizing, decreasing or inhibiting) of an activity. The term "pharmacophore" as used herein refers to the ensemble of steric and electronic features of a particular structure that is necessary to ensure the optimal supramolecular interactions with a specific biological target structure and to trigger (or to block) its biological response. A pharmacophore may or may not represent a real molecule or a real association of functional groups. In embodiments, a pharmacophore is an abstract concept that accounts for the common molecular interaction capacities of a group of compounds towards their target structure. In certain other embodiments, the term can be considered as the largest common denominator shared by a set of active molecules. Pharmacophoric descriptors are used to define a pharmacophore, including H- bonding, hydrophobic and electrostatic interaction sites, defined by atoms, ring centers and virtual points. Accordingly, in the context of ligands, a pharmacophore may represent an ensemble of steric and electronic factors which are necessary to insure supramolecular interactions with a specific biological target structure. As such, a pharmacophore may represent a template of chemical properties for an active site of a protein/enzyme - representing these properties' spatial relationship to one another that theoretically defines a ligand that would bind to that site. The coordinates of the present invention are also used to determine pharmacophores. These pharmacophores may be designed after reviewing results from the use of a docking program, to determine the shape of the 11 HSD1 pharmacophore. Alternatively, programs such as GRID are used to calculate the properties of a pharmacophore. Once the pharmacophore is determined, it may be used to screen chemical libraries for compounds that fit within the pharmacophore. The term "precipitant" as used herein is includes any substance that, when added to a solution, causes a precipitate to form or crystals to grow. Examples of precipitants within the scope of this invention include, but are not limited to, alkali (e.g., Li, Na, or K), or alkaline earth metal (e.g., Mg²⁺, or

Ca²⁺) salts, and transition (e.g., Mn²⁺, or Zn²⁺) metal salts. Common counterions to the metal ions include, but are not limited to, halides, phosphates, citrates and sulfates. The term "prodrug" as used herein refers to drugs that, once administered, are chemically modified by metabolic processes to become pharmaceutically active. In embodiments the term also refers to any compound that undergoes biotransformation before exhibiting its pharmacological effects. Prodrugs can thus be viewed as drugs containing specialized non-toxic protective groups used in a transient manner to alter or to eliminate undesirable properties in the parent molecule. The term "receptor" as used herein refers to a protein or a protein complex in or on a cell that specifically recognizes and binds to a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc.). In a broader sense, the term receptor is used interchangeably with any specific (as opposed to non- specific, such as binding to plasma proteins) drug binding site, also including nucleic acids such as DNA. The term "recombinant protein" refers to a polypeptide which is produced by recombinant DNA techniques, wherein' generally, DNA encoding a polypeptide is inserted into a suitable expression vector which is in turn used to transform a host cell to produce the polypeptide encoded by said DNA. This polypeptide may be one that is naturally expressed by the host cell, or it may be heterologous to the host cell, or the host cell may have been engineered to have lost the capability to express the polypeptide which is otherwise expressed in wild type forms of the host cell. The polypeptide may also be a fusion polypeptide. Moreover, the phrase "derived from", with respect to a recombinant gene, is meant to include within the meaning of "recombinant protein" those proteins having an amino acid sequence of a native polypeptide, or an amino acid sequence similar thereto which is generated by mutations, including substitutions, deletions and truncation, of a naturally occurring form of the polypeptide. The truncated 11 ?HSD1 polypeptides utilized herein are preferably constructed by recombinant techniques. As used herein, the term "selective 11 ?HSD1 inhibitor" refers to a substance, for example a small molecule that effectively inhibits 11/?HSD1. As used herein the term "small molecules" refers to preferred drugs, i.e. organic compounds, as they are orally available (unlike proteins which must be administered by injection or topically). Size of small molecules is generally under 1000 Daltons, but many estimates seem to range between 300 to 700 Daltons. As used herein, the term "transfection" means the introduction of a nucleic acid, e.g., via an expression vector, into a recipient cell by nucleic acid-mediated gene transfer. "Transformation", as used herein, refers to a process in which a cell's genotype is changed as a result of the cellular uptake of exogenous DNA or RNA, and, for example, the transformed cell expresses a recombinant form of a polypeptide or, in the case of anti-sense expression from the transferred gene, the expression of a naturally-occurring form of the polypeptide is disrupted. The term "variant" in relation to the polypeptide sequence in SEQ ID NO:7 or SEQ ID NO:8 or SEQ ID NO: 9, or SEQ ID NO: 15 or SEQ ID NO: 25 include any substitution of, variation of, modification of, replacement of, deletion of, or addition of one or more amino acids from or to the sequence providing a resultant polypeptide sequence for an enzyme having functional 11/JHSD1 activity. The variant may be formed by mutation of the native sequence. Such activity may include reductase and/or dehydrogenase activities. Preferably a variant, homologue, functional fragment or portion, of the 11 ?HSD1 sequences SEQ ID NO: 7 or SEQ ID NO: 8, or SEQ ID NO: 9, or SEQ ID NO: 15 or SEQ ID NO: 25 comprises a polypeptide sequence of at least 5 contiguous amino acids, preferably at least 10 contiguous amino acids, preferably at least 15 contiguous amino acids, preferably at least 20 contiguous amino acids, preferably at least 25 contiguous amino acids, or preferably at least 30 contiguous amino acids. Variants of SEQ ID NO: 7 or SEQ ID NO: 8 include for example one or more amino acid substitutions from the mammalian 11 ?HSD1 sequences noted in published GenBank Accession numbers noted above in addition to those provided herein. One representative variant of SEQ ID NO: 7 includes the addition of seven amino acid residues at the C-terminal end; and specifically "klygrwa". Alternatively SEQ ID NO: 7 could be considered a variant of SEQ ID NO: 8 by deletion of amino acid residues from the C-terminal end. The terms "mutant", "variant", "homologue", "analog", "derivative" or "functional fragment ", are used in relation to the amino acid sequence of the 1 1 ?HSD1 protein or polypeptide sequence which is used to produce a crystal of the present invention. The terms include any substitution of, variation of, modification of, replacement of, deletion of, or addition of one or more amino acids from or to the sequence providing the resultant 1 1 ?HSD1 which is capable of being crystallized. Typically, for the "mutant" , "variant", "homologue", "analog", "derivative" or "functional fragment " used in relation to the amino acid sequence of the protein or polypeptide of the 11 ?HSD1 of the crystal of the present invention, the types of amino acid substitutions that could be made should maintain or enhance the hydrophobicity/hydrophilicity and to enhance solubility and stability of the amino acid sequence. Amino acid substitutions may be made provided that the modified 11βHSD1 retains the ability to be crystallised in accordance with present invention. Amino acid substitutions may include the use of non-naturally occurring analogues. The term "vector" refers to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of preferred vector is an episome, i.e., a nucleic acid capable of extra- chromosomal replication. Preferred vectors are those capable of autonomous replication and/or expression of nucleic acids to which they are linked. Vectors capable of directing the expression of genes to which they are operatively linked are referred to herein as "expression vectors". In general, expression vectors of utility in recombinant DNA techniques are often in the form of "plasmids" which refer generally to circular double stranded DNA loops which, in their vector form are not bound to the chromosome. In the present specification, "plasmid" and "vector" are used interchangeably as the plasmid is the most commonly used form of vector. However, the invention is intended to include such other forms of expression vectors which serve equivalent functions and which become known in the art subsequently hereto. Clones: The nucleotide sequence coding for a truncated 11 HSD1 polypeptide, or functional fragment, derivatives or analogs thereof, including a chimeric protein, thereof, can be inserted into an appropriate expression vector, i.e., a vector which contains the necessary elements for the transcription and translation of the inserted protein-coding sequence. The elements mentioned above are termed herein a "promoter." Thus, the nucleic acid encoding a 11βHSD1 polypeptide of the invention or a functional fragment of 11 ?HSD1 protein, derivatives or analogs thereof, is operationally associated with a promoter in an expression vector of the invention. In preferred embodiments, the expression vector contains the nucleotide sequence coding for the polypeptide comprising the 11 ?HSD1 amino acids listed in SEQ ID NO: 7 or the 11 HSD1 amino acids listed in SEQ ID NO: 8 or the 11/?HSD1 amino acids listed in SEQ ID NO: 9 or the 1 1 ?HSD1 amino acids listed in SEQ ID NO: 15; or the 11βHSD1 amino acids listed in SEQ ID NO: 25. Both cDNA and genomic sequences can be cloned and expressed under the control of such regulatory sequences. An expression vector also preferably includes a replication origin. The necessary transcriptional and translational signals can be provided on a recombinant expression vector. As detailed below, all genetic manipulations described for the 11 ?HSD1 gene in this section, may also be employed for genes encoding a functional fragment of the 11 HSD1 polypeptides described herein, derivatives or analogs thereof, including a chimeric protein thereof. Potential host-vector systems include but are not limited to mammalian cell systems infected with virus, e.g., vaccinia virus, adenovirus, etc.; insect cell systems infected with virus, e.g., baculovirus; microorganisms such as yeast containing yeast vectors; or bacteria transformed with bacteriophage, DNA, plasmid DNA, or cosmid DNA. The expression elements of vectors vary in their strengths and specificities. Depending on the host-vector system utilized, any one of a number of suitable transcription and translation elements may be used. A recombinant 11 ?HSD1 protein of the invention may be expressed chromosomally, after integration of the coding sequence by recombination. In this regard, any of a number of amplification systems may be used to achieve high levels of stable gene expression See Sambrook et al., 1989, infra. A suitable cell for purposes of this invention is one into which the recombinant vector comprising the nucleic acid encoding 1 1 HSD1 protein is cultured in an appropriate cell culture medium under conditions that provide for expression of 11/JHSD1 protein by the cell. Any of the methods previously described for the insertion of DNA fragments into a cloning vector may be used to construct expression vectors containing a gene consisting of appropriate transcriptional/translational control signals and the protein coding sequences. These methods may include in vitro recombinant DNA and synthetic techniques, and in vivo recombination (genetic recombination). Expression of 11 ?HSD1 protein may be controlled by any promoter/enhancer element known in the art, but these regulatory elements must be functional in the host selected for expression. Expression vectors containing a nucleic acid encoding a 11 iHSD1 protein of the invention can be identified by four general approaches: (1 ) amplification (i.e. by PCR) of the desired plasmid DNA or specific mRNA, (2) nucleic acid hybridization, (3) presence or absence of selection marker gene functions, and (4) expression of inserted sequences. In the first approach, the nucleic acids can be amplified to provide for detection of the amplified product. In the second approach, the presence of a foreign gene inserted in an expression vector can be detected by nucleic acid hybridization using probes comprising sequences that are homologous to an inserted marker gene. In the third approach, the recombinant vector/host system can be identified and selected based upon the presence or absence of certain "selection marker" gene functions, e.g., beta-galactosidase activity, thymidine kinase activity, resistance to antibiotics, transformation phenotype, occlusion body formation in baculovirus, etc., caused by the insertion of foreign genes in the vector. In another example, if the nucleic acid encoding 11 HSD1 protein is inserted within the "selection marker" gene sequence of the vector, recombinant vectors containing the 11 JHSD1 protein insert can be identified by the absence of the 11 ?HSD1 protein gene function. In the fourth approach, recombinant expression vectors can be identified by assaying for the activity, biochemical, or immunological characteristics of the gene product expressed by the recombinant vector, provided that the expressed protein assumes a functionally active conformation. A wide variety of host/expression vector combinations may be employed in expressing the nucleic acid sequences of this invention as known by those of skill in the art. Once a particular recombinant DNA molecule is identified and isolated, several methods known in the art may be used to propagate it. Once a suitable host system and growth conditions are established, recombinant expression vectors can be propagated and prepared in quantity. As previously explained, the expression vectors which can be used include, but are not limited to include the following vectors or their derivatives: human or animal viruses such as vaccinia virus or adenovirus; insect viruses such as baculovirus; yeast vectors; bacteriophage vectors (e.g., lambda), and plasmid and cosmid DNA vectors. Vectors can be introduced into the desired host cells by methods known in the art, e.g., transfection, electroporation, microinjection, transduction, cell fusion, DEAE dextran, calcium phosphate precipitation, lipofection (lysosome fusion), use of a gene gun, or a DNA vector transporter. Wu et al., J. Biol. Chem. 267:963-967 (1992); and Wu and Wu, J. Biol. Chem. 263:14621-14624 (1992).

Crystal and Space Groups: X-ray structure coordinates define a unique configuration of points in space. Those skilled in the art understand that a set of structure coordinates for a protein or a protein/ligand complex, or a portion thereof, define a relative set of points that, in turn, define a configuration in three dimensions. A similar or identical configuration can be defined by an entirely different set of coordinates, provided the distances and angles between atomic coordinates remain essentially the same. In addition, a scalable configuration of points can be defined by increasing or decreasing the distances between coordinates by a scalar factor while keeping the angles essentially the same. One of ordinary skill in the art would recognize that solving atomic coordinates of crystal structures of proteins such as 11 ?HSD1 requires a stable, long-lasting source of high-quality protein. One aspect of the present invention relates to a human 11 ?HSD1 crystalline composition comprising a polypeptide with an 11 ?HSD1 amino acid sequence as listed in SEQ ID NO: 9 or SEQ ID NO: 15 or SEQ ID NO: 25 or variants thereof. Another aspect of the invention relates to the use of 11^HSD1 from other species, e.g. guinea pig, for crystal structures. The relative conservation of the amino acid sequences of various species at the binding region is shown in FIG. 8. In one embodiment, the present invention discloses a crystalline 1 1βHSD1 molecule comprising a polypeptide with an 11/JHSD1 amino acid sequence as listed in SEQ ID NO: 7 or 11/?HSD1 amino acids as listed in SEQ ID NO: 8 complexed with one or more ligands. In another embodiment, the crystallized complex is characterized by the structural coordinates listed in one of FIG. 6, FIG. 9 or FIG. 10 or portions thereof. In embodiments, the atoms of ligands are optimal within about 5, 7, or 10 angstroms of one or more 11^HSD1 amino acids in SEQ ID NO: 7. One embodiment of the crystallized complex is characterized as belonging to the P21212 space group and has unit cell dimensions of about a=171.080 A, b=62.831 A, c=81.60 A, a=β=γ=90.Q°. This embodiment is encompassed by the structural coordinates of FIG. 6. The ligand may be a small molecule which binds to a 11 ?HSD1 defined by the coordinates of FIG. 6, or portions thereof, with a K| of less than about 10 μM, 1 μM, 500 nM, 100 nM, 50 nM, or even 10 nM. In other embodiments, the ligand is a substrate or substrate analog of 11^HSD1. In a preferred embodiment the ligand is an inhibitor of human 11 HSD1. Various computational methods can be used to determine whether a molecule or a binding pocket portion thereof is "structurally equivalent," defined in terms of its three-dimensional structure, to all or part of 11 ?HSD1 or its binding pocket(s). Such methods may be carried out in current software applications, such as the molecular similarity application of QUANTA (Accelrys Inc., San Diego, Calif.).

The molecular similarity application permits comparisons between different structures, different conformations of the same structure, and different parts of the same structure. The procedure used in molecular similarity to compare structures is divided into four steps: (1 ) load the structures to be compared into a computer; (2) optionally define the atom equivalences in these structures; (3) perform a fitting operation; and (4) analyze the results. Each structure is identified by a name. One structure is identified as the target (i.e., the fixed structure); all remaining structures are working structures (i.e., moving structures). Since atom equivalency within molecular similarity applications is defined by user input, for the purpose of this invention equivalent atoms are defined as protein backbone atoms (N, Ca., C, and O) for all conserved residues between the two structures being compared. A conserved residue is defined as a residue that is structurally or functionally equivalent (See Table 3 infra). In embodiments rigid fitting operations are considered. In other embodiments, flexible fitting operations may be considered. When a rigid fitting method is used, the working structure is translated and rotated to obtain an optimum fit with the target structure. The fitting operation uses an algorithm that computes the optimum translation and rotation to be applied to the moving structure, such that the root mean square difference of the fit over the specified pairs of equivalent atoms is an absolute minimum. This number, given in angstroms, is reported by the molecular similarity application. For the purpose of this invention, any molecule or molecular complex or binding pocket thereof, or any portion thereof, that has a root mean square deviation of conserved residue backbone atoms (N, Ca., C, and O) of less than about 2.5 A, 2.0 A, 1.7A 1.5 A, 1.25 A, 1.0 A, 0.7 A, 0.5 A, 0.25 A, or even 0.2 A, when superimposed on the relevant backbone atoms described by the reference structure coordinates listed in one of FIG. 6, FIG. 9 or FIG. 10 is considered structurally equivalent" to the reference molecule. That is to say, the crystal structures of those portions of the two molecules are substantially identical, within acceptable error. Particularly preferred structurally equivalent molecules or molecular complexes are those that are defined by the entire set of structural coordinates listed in FIG. 6, FIG. 9 or FIG. 10 plus or minus a root mean square deviation from the conserved backbone atoms of those amino acids of not more than about 2.0 A. More preferably, the root mean square deviation is less than about 1.0 A. The term "root mean square deviation" means the square root of the arithmetic mean of the squares of the deviations. It is a way to express the deviation or variation from a trend or object. For purposes of this invention, the "root mean square deviation" defines the variation in the backbone of a protein from the backbone of 11 ?HSD1 or a binding pocket portion thereof, as defined by the structural coordinates of 11 JHSD1 described herein. The refined x-ray coordinates of the guinea pig 11/JHSD1 as provided in SEQ ID NO: 7 are as listed in FIG. 6. The refined x-ray coordinates of a guinea pig 11^HSD1 Form 2 as provided in SEQ ID NO: 8 are as listed in FIG. 9. The refined x-ray coordinates of a human 11βHSD1 as provided in SEQ ID NO: 15 are as listed in FIG. 10. The refined x-ray coordinates of guinea pig 11 ?HSD1 (Form 2) co-complexed with glycyrrhetinic acid are listed in FIG. 11. Schematic views of the 11/JHSD1 crystal molecule are shown in FIG. 1 and FIG. 2. The crystal structure of FIG. 6 is composed of a single domain of 9 a helices and 8 3₁₀ helices arranged in a compact fold (FIG. 1 ). The numbering of the helices is as shown below. We have followed the helice numbering convention provided by Huai et al, Structure, 11 :865-873 (2003), and the start and end points of the helices are determined according to Kabsch and Sander, Biopolymers, 22: 2577-2637 (1983). Description of Crystal Structure and Active Site: The refined x-ray coordinates of guinea pig 11/?HSD1 , Form 1 , with three identical polypeptide chains, three molecules of bound NADP+ and 179 water molecules are as listed in FIG. 6. An orthogonal view of the three molecules preferred to be observed in the asymmetry unit in the current crystal form is shown in FIG. 1. In FIG. 1 the three 11βHSD1 molecules are identical. The polypeptide chains are in ribbon representation. The bound NADP+ are shown as balls. Polypeptide chain A forms a dimer with chain C. Polypeptide chain B forms a similar dimer with a symmetry related molecule. Dimehzation of 11 ?HSD1 was observed for proteins purified from human liver microsomes (Maser et al., Biochemistry, 41 :2459-2465 (2002)). These dimers were observed in the crystal and are of physiological relevance for activity. Two orthogonal views of the 11/JHSD1 dimer (as represented by chain A and chain C) mentioned above are shown in FIG. 2 and FIG. 3. The polypeptide chains are in ribbon representation. Bound NADP+ are shown as a stick model. To ease visualization, cortisol (shown as a ball model) was modeled in to indicate active sites. The structure of each polypeptide domain is composed of 9 a helices, 8 beta strands and 2 3₁₀ helices arranged in a compact fold (FIG. 4 and FIG. 5 and Table 1 ). The structure is essentially of the "alβ" type, including a N-terminus Rossmann fold. Numbering of the secondary structures in 11/JHSD1 follows the convention established for 17B-hydroxysteroid Dehydrogenase by Breton et al., Structure, 4:905-915 (1996). The start and end points of the secondary structures are determined according to Kabsch and Sander, Biopolymers, 22(12): 2577-637 (1983). The numbering of the secondary structures is as shown in Table 1. No electron density is observed for residues 289-293, which probably is in a flexible conformation. Also, 19 residues at the N-terminus (17 residues from the expression vector, plus Asn24 and Glu25) are disordered with no electron density observed. Within the overall fold of each polypeptide, two sub-domains can be defined. The first sub-domain is composed of residues 26-118 (βA, σB, βB, σC, βC, σD and βD), 131-217 (σE, βE, a? and βF) and 235-259 (σB and βG). This is the NADP⁺ binding domain, also known as Rossmann fold (FIG. 4 & FIG. 5 for chain

C). Residues that are within 5A distance to the bound NADP⁺ are listed in Table 5. These residues are either directly involved in binding to the NADP⁺ or indirectly involved in NADP⁺ binding by affecting local conformation. The second sub-domain contains residues 119-130 (βD1), 218-234 (σF1) and 260-288 (σG1 and aG2). This sub-domain forms the basis for substrate (cortisol/cortisone) binding (FIG. 4 and FIG. 5, for chain C). Each monomer of the active dimer described above contains a substrate-binding pocket at the dimer interface formed by residues from its own (residues 119-130, residues 218-234 and residues 260-269) as well as residues from the σG2 (residues 270-288) helix of the other monomer. Residues from the Rossmann fold also contribute to the binding of substrate. Residues (Ser170, Tyr183 and Lys187) forming the catalytic triad are positioned in the center of the substrate-binding pocket in the vicinity of the nicotiamide ring of

NADP⁺. The surface of the substrate-binding pocket is lined with side chains from aromatic (Phe or Tyr) or hydrophobic residues (Val, Leu, lie, Met etc) consistent with its role of binding the hydrophobic cortisone or cortisol. Table 2 lists residues of the substrate-binding pocket. These residues will be directly involved in substrate or inhibitor binding. Residues close to the residues listed in Table 2 might also affect inhibitor binding by modify/stabilize local conformations. These additional residues are listed in Table 3. An important feature of the 11 ?HSD1 protein revealed by the current structure is the additional membrane association region. The first 23 residues in the N-terminus of 11 5HSD1 have been suggested to form a trans-membrane helix. The current structure shows that some hydrophobic residues from the last two helices (σG1 and σG2) and those in the vicinity are highly exposed to the solvent. This implicates that this region might be involved in membrane-binding. Indeed, when this region is anchored to the membrane (as shown in FIG. 7), the N-terminus of each monomer is also well positioned to be able to connect to the transmembrane helix formed by the first 23 residues. FIG. 8 shows an alignment of the C-terminus region of 11βHSD1 across different species. It indicates that key residues involved in membrane binding are conserved and thus membrane-binding through this region might be a common feature in these species. The entrance to the cortisol/contisone binding-pocket is also located close to the membrane. This allows the quick diffusion of the less water-soluble cortisone/cortisol into and out of the active site from the lipid membrane. Table 4 lists residues form the cortisone/cortisol entrance to the active site pocket. Accordingly, the present invention provides a molecule or molecular complex that includes an entire active enzyme of 11/JHSD1 , the co-factor-binding pocket, the substrate-binding pocket and the entrance to the substrate-binding pocket. In one embodiment, the HβHSDI substrate and cofactor binding pockets include the amino acids as listed in Table 2, Table 3, Table 4 or Table 5, and more preferably the amino acids listed in Table 2 and Table 3, the binding pockets being defined by a set of points having a root mean square deviation of less than about 2.0, 1.7, 1.5, 1.2, 1.0, 0.7, 0.5, or even 0.2 A, from points representing the backbone atoms of the amino acids in Table 2, Table 3, Table 4 or Table 5. The present invention also includes the membrane association region (σG1 , σG2 and vicinity). Mutation of these exposed hydrophobic residues to hydrophilic residues will have the potential to increase the solubility and stability of recombinantely expressed 11/JHSD1 proteins. The guinea pig structure can be used to guide the design of constructs that express more soluble/stable 11 ?HSD1 proteins for application in drug discovery. In one embodiment, amino acid residues that can be modified to enhance solubility/stability and activity are listed in Table 6 and Table 7. This type of enhancement can be performed on 11 ?HSD1 proteins from guinea pig, human and other mammalian species. The improved protein may thus serve as enhanced reagent for HTS and for crystallography studies. Table 1 : Secondary Structure assignment of guinea pig 11 ?HSD1 structure (according to Kabsch and Sander, Biopolymers, 22(12): 2577-637 (1983)). Underlined characters indicate the' Rossmann fold, and the rest indicate the substrate-binding region.

Accordingly, the present invention provides a molecule or molecular complex that includes at least a portion of an 11 JHSD1 and/or a substrate binding pocket. In one embodiment, the 11^HSD1 binding pocket includes the amino acids listed in Table 1 , preferably the amino acids listed in Table 2, and more preferably the amino acids listed in Table 2 and Table 3, the binding pocket being defined by a set of points having a root mean square deviation of less than about 2.0, 1.7, 1.5, 1.2, 1.0, 0.7, 0.5, or even 0.2 A, from points representing the backbone atoms of the amino acids in Tables 2-3. In another embodiment, the 11^HSD1 substrate binding pocket includes one or more amino acids selected from S170, Y177, Y183 and/or T227 species related or consecutive amino acid substitutions including the above noted 11 HSD1 amino acids from SEQ ID NO: 7 or SEQ ID NO: 8. Table 2:¹ Residues of the substrate-binding pocket of guinea pig 11 iHSD1. Underlined characters indicate residues from the other monomer in the dimer.

Table 3: Residues close to residues listed in Table 2. These residues may also affect the binding of substrate or inhibitors. Underlined characters indicate residues from the other monomer in the dimer.

Table 4: Residues at the Entrance/Exit of Cortisol/Cortisone. Underlined characters indicate residues from the other monomer in the dimer.

Table 5: Residues within 5A from NADP⁺

Table 6: Exposed surface hydrophobic residues in guinea pig 11 ?HSD1.

Table 7: Exposed surface hydrophobic residues in human 11 JHSD1. These residues are predicted using a homology model based on the guinea pig 11 ?HSD1 structure.

Isolated Polypeptides and Variants: One embodiment of the invention describes an isolated polypeptide consisting of a portion of 11yffHSD1 which functions as a binding site when folded in the proper 3-D orientation as listed for example in one of FIG. 6, FIG. 9 or FIG. 10. Another embodiment is an isolated polypeptide comprising a portion of 11 ?HSD1 , wherein the portion starts at about amino acid residue 24 of the N-terminus, and ends at about the last amino acid residue at the C-terminus as described in SEQ ID NO:6, (amino acid residues N24 to E293 numbering according to AF188005, except for the A103V substitution); or a sequence that is at least 95%, or 98% homologous or an equivalent to a polypeptide with an 11/JHSD1 amino acid sequence as listed in SEQ ID NO:6 or to the 11 HSD1 amino acids as listed in SEQ ID NO:7 or to the 11βHSD1 amino acids as listed in SEQ ID NO:8 or to the 11 HSD1 amino acids as listed in SEQ ID NO: 14; or to the 1 1 HSD1 amino acids as listed in SEQ ID NO: 24. Purification rationale: Both guinea pig and human 11 ?HSD1 are insoluble after expression in Ecoli under standard conditions. So, it is necessary to use detergent to solubilize the protein to achieve reasonable yield and maintain protein stability. It was noted that recombinant HSD1 can be solubilized in n-Dodecyl β-D-maltoside (β-DDM) with decent yield and good activity. β-DDM is a non-ionic detergent that is compatible with protein crystallization. Basically, a similar protocol is used for the purification of guinea pig and human HSD1. However, there two differences. First, human 11 ?HSD1 is more insoluble than guinea pig 11 ?HSD1. Thus, higher concentration of β-DMM (0.4%) was employed to solubilize human 11/JHSD1. The other difference is that higher pH (pH 7.5) was used in Q-sepharose and Superdex columns for human HSD1 while pH 7.0 was used for guinea pig 11^HSD1. Advantages of the purification process include: decent yield with good stability and activity; purity more than 95%; removed detergent β-DDM in the late purification steps for guinea pig 11/JHSD1 and human 11/?HSD1 Mutant B, Mutant C mutants (Q-sepharose column, Superdex column); and removed 6xHis tag that may interfere the activity or • crystallization. Advantages of human 11 ?HSD1 Mutant B and Mutant C constructs include: dramatically improve protein properties (solubility, activity, homogeneity, yield, stability); their activities are compatible with that of guinea pig 11 JHSD1 ; greatly improved solubility and stability so that detergents can be omitted in the late purification steps. (Q- sepharose, Superdex column); highly homogenous species can be obtained for crystallization study; highly reproducible; and.eliminate the complexity and heterogeneity of adding detergents in the purified proteins. Human 11βHSD1 Mutant B and Mutant C further improved their solubility and homogeneity. (See Table 8.) SEQ ID NO: 9 has improved properties relative to previously studied sequences of human 11 ?HSD1 such as a truncated human sequence having a point mutation at C272S from the wild type (Walker, et al., J. Biol. Chem., 276:21343-21350 (2001 )). These two human sequences of 11 5HSD1 have similar Michaelis-Menten constants k_cat and K_m for the reduction of cortisone in the presence of an excess of NADPH (500uM, final concentrations). However, the human 11 ?HSD1 of SEQ ID NO: 9 is more active in solution compared to the human 11 ?HSD1 with a point mutation of C272S. These results suggest that the activity difference observed between these two sequences of human 11 ?HSD1 is associated with a higher proportion of active enzyme for the SEQ ID NO:8 rather than differences in the kinetic profile toward the substrate. Table 8. Activity of Mutant Sequences (larger k cat/km and higher % active is better)

One embodiment of the invention comprises crystalline compositions comprising variants of 11 ?HSD1. Variants of the present invention may have an amino acid sequence that is different by one or more amino acid substitutions to the 11 ?HSD1 sequences disclosed in SEQ ID NO: 7 or SEQ ID NO: 8 or SEQ ID NO: 9 or SEQ ID NO: 15 or SEQ ID NO: 25 and in the GenBank amino acid sequences noted above. Embodiments which comprise amino acid deletions and/or additions may also be provided. The variant may have conservative changes (amino acid similarity), wherein a substituted amino acid has similar or enhanced structural or chemical properties, for example, the replacement of leucine with isoleucine. Guidance in determining which and how many amino acid residues may be substituted, inserted, or deleted without adversely affecting biological or proposed pharmacological activity may be reasonably inferred in view of this disclosure, and may further be found using computer programs well known in the art, for example, DNAStar® software. * Amino acid substitutions may be made, for instance, on the basis of similarity in polarity, charge, solubility, hydrophobicity, hydrophilicity, and/or the amphipathic nature of the residues as long as a biological and/or pharmacological activity of the native molecule is retained. Negatively charged amino acids include aspartic acid and glutamic acid; positively charged amino acids include lysine and arginine; amino acids, with uncharged polar head groups having similar hydrophilicity values include leucine, isoleucine, and valine; amino acids with aliphatic head groups include glycine, alanine; asparagine, glutamine, serine; and amino acids with aromatic side chains include phenylalanine, and tyrosine. Table 9: Examples of conservative substitutions are set forth as follows:

"Homology" is a measure of the identity of nucleotide sequences or amino acid sequences. In order to characterize the homology, subject sequences are aligned so that the highest percentage homology (match) is obtained, after introducing gaps, if necessary, to achieve maximum percent homology. N- or C-terminal extensions shall not be construed as affecting homology. "Identity" has an art-recognized meaning and can be calculated using published techniques. Computer program methods to determine identity between two sequences, for example, include DNAStar® software (DNAStar Inc. Madison, WI); the GCG® program package (Devereux, J., et al., NAR, 12:387 (1984); BLASTP, BLASTN, FASTA (Atschul, S.F. et al., J. Mol. Bio., 215: 403 (1990). Homology as defined herein is determined conventionally using the well-known computer program, BESTFIT® (Wisconsin Sequence Analysis Package, Version 8 for Unix, Genetics Computer Group, University Research Park, 575 Science Drive, Madison, WI, 53711 ). When using BESTFIT® or any other sequence alignment program (such as the Clustal algorithm from MegAlign software (DNAStar®) to determine whether a particular sequence is, for example, about 90% homologous to a reference sequence, according to the present invention, the parameters are set such that the percentage of identity is calculated over the full length of the reference nucleotide sequence or amino acid sequence and that gaps in homology of up to about 90% of the total number of nucleotides in the reference sequence are allowed. Ninety percent of homology, as an example, is therefore determined using the BESTFIT® program with parameters set such that the percentage of identity is calculated over the full length of the reference sequence, e.g., GenBank Accession Nos: M76665; AF188005; X83202; S75207; J05107; S63400; Q7M3I4; X69561 and AF414124, and wherein up to 10% of the amino acids in the reference sequence may be substituted with another amino acid. Percent homologies are likewise determined, for example, to identify preferred species, within the scope of the claims appended hereto, which reside within the range of about 90% to 100% homology to 11βHSD1 sequences of SEQ ID NO: 7 or SEQ ID NO: 8 or SEQ ID NO: 9 or SEQ ID NO: 15 or SEQ ID NO: 25 as well as the binding site thereof. As noted above, N- or C-terminal extensions shall not be construed as affecting homology. Thus, when comparing two sequences, the reference sequence is generally the shorter of the two sequences. This means that, for example, if a sequence of 50 nucleotides in length with precise identity to a 50 nucleotide region within a 100 nucleotide polynucleotide is compared, there is 100% homology as opposed to only 50% homology. Although the 110HSD1 polypeptides of SEQ ID NOS: 7-9 and SEQ ID NO: 15 and SEQ ID NO: 25. and a variant polypeptide may only possess a certain percentage identity, e.g., 90%, they are actually likely to possess a higher degree of similarity, depending on the number of dissimilar codons that are conservative changes. Conservative amino acid substitutions can frequently be made in a protein without altering either the conformation or function of the protein. Similarity between two sequences includes direct matches as well a conserved amino acid substitutes which possess similar structural or chemical properties, e.g., similar charge as described in Table 9. Percentage similarity (conservative substitutions) between two polypeptides may also be scored by comparing the amino acid sequences of the two polypeptides by using programs well known in the art, including the BESTFIT program, by employing default settings for determining similarity. A further embodiment of the invention is a crystal comprising the coordinates of FIG. 6, wherein the 11βHSD1 amino acid sequence is provided in SEQ ID NO: 7 (N24-E293). A further embodiment of the invention is a crystal comprising the coordinates of FIG. 6, wherein the amino acid sequence is at least 95%, or 98% homologous to the amino acid sequence represented by SEQ ID NO:7 (N24-E293). A higher degree of sequence conservation would be preferred in the binding site. Various methods for obtaining atomic coordinates of structurally homologous molecules and molecular complexes using homology modeling are known by those of skill in the art. A further embodiment of the invention is a crystal comprising the coordinates of FIG .9, wherein the guinea pigl 1βHSD1 amino acid sequence provided in SEQ ID NO: 8 (N24 to A300). A further embodiment of the invention is a crystal comprising the coordinates of FIG. 9, wherein the amino acid sequence is at least 95%, or 98% homologous to the amino acid sequence represented by SEQ ID NO: 8 (N24-A300). A higher degree of sequence conservation would be preferred in the binding site. Various methods for obtaining atomic coordinates of structurally homologous molecules and molecular complexes using homology modeling are known by those of skill in the art. A further embodiment of the invention is a crystal comprising the coordinates of FIG. 10, wherein the 11/JHSD1 amino acid sequence is provided in SEQ ID NO: 15. A further embodiment of the invention is a crystal comprising the coordinates of FIG. 10, wherein the amino acid sequence is at least 95%, or 98% homologous to the amino acid sequence represented by SEQ ID NO: 15. A higher degree of sequence conservation would be preferred in the binding site. Various methods for obtaining atomic coordinates of structurally homologous molecules and molecular complexes using homology modeling are known by those of skill in the art. Structure Based Drug Design: Once the three-dimensional structure of a crystal comprising a 11/JHSD1 protein, a functional domain thereof, homologue fragment, variant analogue or derivative thereof, is determined, a potential inhibitor may be examined through the use of computer modeling using a docking program such as GRAM, DOCK, or AUTODOCK. See for example, Morris et al., J. Computational Chemistry, 19:1639- 1662 (1998). This procedure can include in silico fitting of potential ligands to the 11βHSD1 crystal structure to ascertain how well the shape and the chemical structure of the potential ligand will complement or interfere with 11^HSD1 (Bugg et al., Sci. Am., 92-98 (1993); and West et al., TIPS, 16:67- 74 1995)). Computer programs can also be employed to estimate the attraction, repulsion, and steric hindrance of the ligand to the binding site. Generally the tighter the fit (e.g., the lower the steric hindrance, and/or the greater the attractive force) the more potent the potential drug will be since these properties are consistent with a tighter binding constant. Furthermore, the more specificity in the design of a potential drug the more likely that the drug will not interfere with the properties of other proteins. This will minimize potential side-effects due to unwanted interactions with other proteins. One embodiment of the present invention relates to a method of identifying an agent or chemical compound that binds to a binding site on 11βHSD1 binding domain wherein the binding site comprises one or more 11βHSD1 amino acid residues provided in one of SEQ ID NO:7 or SEQ ID NO: 8 or SEQ ID NO: 9 or SEQ ID NO: 15 or SEQ ID NO: 25 or to amino acid sequences corresponding to the GenBank deposits noted above, comprising contacting 11 ?HSD1 with a test ligand under conditions suitable for ^■ binding of the test ligand to the binding site, and determining whether the test ligand binds in the binding site, wherein if binding occurs, the test ligand is an agent that binds in the binding site. In embodiments, the testing may be carried out in silico using a variety of molecular modeling software algorithms including, but not limited to, DOCK, ALADDIN, CHARMM simulations, AFFINITY, C2-LIGAND FIT, Catalyst, LUDI, CAVEAT, and CONCORD. Brooks et al., J. Comp. Chem., 4:187-217 (1983); and Meng et al., J. Comp. Chem., 13:505-524 (1992). In another embodiment, a potential ligand may be obtained by screening a random peptide library prpduced by a recombinant bacteriophage (Scott and Smith, Science, 249:386-390, (1990); Cwirla et al., PNAS., 87:6378-6382 (1990); Devlin et al., Science, 249:404-06 (1990)), or a chemical library, or the like. A ligand selected in this manner can be then be systematically modified by computer modeling programs until more promising potential ligands are identified. Such analysis has been shown to be effective in the development of HIV protease inhibitors (Lam et al., Science 263:380-84 (1994); Wlodawer et al., Ann. Rev. Biochem. 62:543-585 (1993); Appelt, Perspectives in Drug Discovery and Design, 1 :23-48 (1993); and Erickson, Perspectives in Drug Discovery and Design, 1 :109-128 (1993)). Such computer modeling allows the selection of a finite number of rational chemical modifications, as opposed to the countless number of essentially random chemical modifications that could be made, and of which any one might lead to a useful drug. Each chemical modification requires additional chemical steps, which while being reasonable for the synthesis of a finite number of compounds, quickly becomes overwhelming if all possible modifications needed to be synthesized are actually synthesized. Thus, through the use of the three-dimensional structure disclosed herein and computer modeling, a large number of these compounds can be rapidly screened on a computer monitor screen, and a few likely candidates can be determined without the laborious synthesis of large numbers of compounds. Once a potential ligand is identified, it can be either selected from a library of chemicals, or alternatively, the potential ligand may be synthesized de novo. As mentioned above, the de novo synthesis of one or even a relatively small group of specific compounds is reasonable in the art of drug design. The prospective drug can be placed into any standard binding assay described herein to test its effect on 11βHSD1 interaction. When a suitable drug is identified, a supplemental crystal can be grown which comprises a protein-ligand complex formed between an 11 ?HSD1 protein and the drug. Preferably the crystal effectively diffracts X-rays allowing the determination of the atomic coordinates of the protein-ligand complex to a resolution of less than 5.0 A , more preferably less than 3.0 A, and even more preferably less than 2.0 A. The three-dimensional structure of the supplemental crystal can be determined by Molecular Replacement Analysis. Molecular replacement involves using a known three-dimensional structure as a search model to determine the structure of a closely related molecule or protein-ligand complex in a new crystal form. The measured X-ray diffraction properties of the new crystal are compared with the search model structure to compute the position and orientation of the protein in the new crystal. Computer programs that can be used include: X-PLOR and AMORE (Navaza, Ada Crystallographies ASO, 157-163 (1994)). Once the position and orientation are known, an electron density map can be calculated using the search model to provide X-ray phases. Thereafter, the electron density is inspected for structural differences, and the search model is modified to conform to the new structure. Using this approach, it is possible to use the claimed structure of 11 SHSD1 to solve the three-dimensional structures of any such 11 ?HSD1 complexed with a new ligand. Other computer programs that can be used to solve the structures of such STAT crystals include QUANTA, CHARMM; INSIGHT; SYBYL; MACROMODEL; and ICM.

Ligands: In one aspect, the present invention provides the means to identify ligands, including, for example, chemical compounds, etc. which interact with a binding site of the 11^HSD1 defined by a set of points having a root mean square deviation of less than about 2.0 A from points representing the backbone atoms of the amino acids represented by the structure coordinates listed in one of FIG. 6, FIG. 9 or FIG. 10. A further embodiment of the present invention comprises agents which interact with a binding site of 11βHSD1 defined by a set of points having a root mean square deviation of less than about 2.0, 1.7, 1.5, 1.2, 1.0, 0.7, 0.5, or even 0.2 A from points representing the backbone atoms of the amino acids represented by the structure coordinates listed in one of FIG. 6, FIG. 9 or FIG. 10. Such embodiments represent variants of the 11βHSD1 crystal. In another aspect, the present invention describes ligands, which bind to correctly folded polypeptides comprising an amino acid sequence spanning the 11jSHSD1 amino acids listed in SEQ ID NO: 7 or SEQ ID NO:8, or SEQ ID NO: 9 or SEQ ID NO: 15 or SEQ ID NO: 25 or a homologue, or a variant thereof. In embodiments, the ligand is a competitive or uncompetitive inhibitor of 11 ?HSD1. One embodiment of the present invention relates to agents or ligands, such as proteins, peptides, peptidomimetics, small organic molecules, etc., designed or developed with reference to the crystal structure of 11/JHSD1 as represented by the coordinates presented herein in FIG. 6, and portions thereof. Such agents interact with the binding site of the 11βHSD1 represented by one or more amino acid residues selected from those provided in Tables 2-5 or selected or species specific substitutions thereof. Machine Readable Storage Media: Transformation of the structure coordinates for all or a portion of 11^HSD1 , or the 11/JHSD1/ligand complex or a binding pocket, for structurally homologous molecules as defined below, or for the structural equivalents of any of these molecules or molecular complexes as defined above, into three-dimensional (3D) graphical representations of the molecule or complex can be conveniently achieved through the use of commercially-available software. The invention thus further provides a machine-readable storage medium comprising a data storage material encoded with machine readable data which, when using a machine programmed with instructions for using said data, is capable of displaying a graphical three-dimensional representation of any of the molecule or molecular complexes of this invention that have been described above. In a preferred embodiment, the machine-readable data storage medium comprises a data storage material encoded with machine readable data which, when using a machine programmed with instructions for using said data, is capable of displaying a graphical three-dimensional representation of a molecule or molecular complex comprising all or any parts of a 11^HSD1 substrate binding pocket, as defined above. In another preferred embodiment, the machine-readable data storage medium is capable of displaying a graphical three-dimensional representation of a molecule or molecular complex defined by the structure coordinates listed in one of FIG. 6, or FIG. 9 or FIG. 10 plus or minus a root mean square deviation from the backbone atoms of said amino acids of not more than 2.0 A. In an alternative embodiment, the machine-readable data storage medium comprises a data storage material encoded with a first set of machine readable data which comprises the Fourier transform of the structural coordinates set forth in one of FIG. 6, FIG. 9 or FIG. 10 or FIG. 11 and which, when using a machine programmed with instructions for using said data, 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 corresponding to the second set of machine readable data. For example, a system for reading a data storage medium may include a computer comprising a central processing unit ("CPU"), a working memory which may be, e.g., RAM (random access memory) or "core" memory, mass storage memory (such as one or more disk drives or CD-ROM drives), one or more display devices (e.g., cathode-ray tube ("CRT") displays, light emitting diode ("LED") displays, liquid crystal displays ("LCDs"), electroluminescent displays, vacuum fluorescent displays, field emission displays ("FEDs"), plasma displays, projection panels, etc.), one or more user input devices (e.g., keyboards, microphones, mice, touch screens, etc.), one or more input lines, and one or more output lines, all of which are interconnected by a conventional bidirectional system bus. The system may be a stand-alone computer, or may be networked (e.g., through local area networks, wide area networks, intranets, extranets, or the internet) to other systems (e.g., computers, hosts, servers, etc.). The system may also include additional computer controlled devices such as consumer electronics and appliances. Input hardware may be coupled to the computer by input lines and may be implemented in a variety of ways. Machine-readable data of this invention may be inputted via the use of a modem or modems connected by a telephone line or dedicated data line. Alternatively or additionally, the input hardware may comprise CD-ROM drives or disk drives. In conjunction with a display terminal, a keyboard may also be used as an input device. Output hardware may be coupled to the computer by output lines and may similarly be implemented by conventional devices. By way of example, the output hardware may include a display device for displaying a graphical representation of a binding pocket of this invention using a program such as QUANTA as described herein. Output hardware might also include a printer, so that hard copy output may be produced, or a disk drive, to store system output for later use. In operation, a CPU coordinates the use of the various input and output devices, coordinates data accesses from mass storage devices, accesses to and from working memory, and determines the sequence of data processing steps. A number of programs may be used to process the machine-readable data of this invention. Such programs are discussed in reference to the computational methods of drug discovery as described herein. References to components of the hardware system are included as appropriate throughout the following description of the data storage medium. Machine-readable storage devices useful in the present invention include, but are not limited to, magnetic devices, electrical devices, optical devices, and combinations thereof. Examples of such data storage devices include, but are not limited to, hard disk devices, CD devices, digital video disk devices, floppy disk devices, removable hard disk devices, magneto-optic disk devices, magnetic tape devices, flash memory devices, bubble memory devices, holographic storage devices, and any other mass storage peripheral device. It should be understood that these storage devices include necessary hardware (e.g., drives, controllers, power supplies, etc.) as well as any necessary media (e.g., disks, flash cards, etc.) to enable the storage of data. The present invention is further illustrated by the following examples which should not be construed as limiting in any way. The practice of the present invention will employ, unless otherwise indicated, conventional techniques of cell biology, cell culture, molecular biology, microbiology and recombinant DNA, X-ray crystallography, and molecular modeling which are within the skill of the art. Such techniques are explained fully in the literature and known to those of skill in the pertinent arts. See, for example, Molecular Cloning: A Laboratory Manual, 2nd Ed., ed. by Sambrook, Fritsch and Maniatis (Cold Spring Harbor Laboratory Press (1989)); DNA Cloning, Volumes I and II (D. N. Glover ed., (1985)); Oligonucleotide Synthesis (M. J. Gait ed., (1984)); U.S. Patent No: 4,683,195; Nucleic Acid Hybridization (B. D. Hames & S. J. Higgins eds. (1984)); Transcription And Translation (B. D. Hames & S. J. Higgins eds. (1984)); B. Perbal, A Practical Guide To Molecular Cloning (1984); the treatise, Methods In Enzymology (Academic Press, Inc., N.Y.); Methods In Enzymology, Vols. 154 and 155 (Wu et al. eds.), Crystallography Made Crystal Clear: A Guide for Users of Macromolecular Models (Gale Rhodes, 2^nd. Ed. San Diego; Academic Press, (2000)). EXAMPLES

Example 1

CLONING, SUB-CLONING AND DNA/PROTEIN SEQUENCES OF GUINEA PIG AND HUMAN 11/JHSD1 : The full-length DNA of guinea pig 11/JHSD1 used in this work was cloned from a First Strand cDNA from guinea pig liver (Gene Link Inc.). A expand High Fidelity^plus PCR kit (Roche Applied Science) and two pairs of primers (Forward: atggcttttctgaaaaaataccttc (SEQ ID NO:1 ); Reverse: tcatgcccaccttccatag (SEQ ID NO:2) were used for the PCR reaction. The resulting guinea pig 11 ?HSD1 DNA sequence matches well with the Genebank sequence AF188005 with only two mismatches. The first mismatch is at position 355 (as numbered in AF 188005, the coding region of AF188005 is between 48-950). A "c" in AF188005 position 355 is changed to a "t" in the gene cloned for this work. The second change is at position 611 (as numbered in AF188005), a "t" in AF 188005 is changed to a "c" in the gene used for this work. The first change led to a single amino acid change (A103 in Genebank AF188005 or SWISS/Prot Q9QZE1 , and V103 in this work). The second change is a silent mutation as the translated protein sequence is not affected. Both changes are likely due to polymorphorisms. The first change was observed and discussed previously (Shafqat et al. J. Biol. Sci., 278:2030-2035 (2003). The first 23 amino acids of 11 ?HSD1 were predicted to be a trans-membrane helix. For the ease of expression, purification and subsequent crystallization, residues from N24 to E293 were sub-cloned into a pET28a vector. Two primers were used to insert the guinea pig 11 ?HSD1 sequence into pET28a between BamH I and Xho I sites: forward: cgggatccaatgagaagttcagaccag (SEQ. ID NO:3); reverse: aaaactcgagtcactcgttgcttaatacattgtc (SEQ ID NO:4). Sequence 5: DNA sequence of guinea pig 11 7HSD1 in pET28a vector for soluble expression in E. coli. Upper case characters indicate that the sequence comes from the pET28a vector, and the lower case characters indicate the sequence of guinea pig 11 ?HSD1. The DNA of 11/?HSD1 (as shown below) was subcloned into the pET28a vector through the BamH I and Xho I sites.

ATGGGCAGCAGCCATCATCATCATCATCACAGCAGCGGCCTGGTGCCGCGCGGCAGCCATATGGCTA GCATGACTGGTGGACAGCAAATGGGTCGCGGATCCaatgagaagttcagaccagagatgctccaaggaaagaaagtgatt gtcacaggggccagcaaagggattggaagagaaatagcttatcatctggcaaagatgggagcccacgtggtggtgacagcgaggtcaaaagaag ccctacagaaggtggtggcccgctgcttagaacttggagcagcctcagcacactacattgctggcagcatggaagacatgacctttgcagaagagtttg ttgcagaagcaggaaatctcatgggaggactagacatgcttattctcaaccacgtcctctacaatcgtctgactttttttcatggtgagatcgacaacgtacg caaaagcatggaggtcaactttcacagttttgtggtcctgagcgtagctgcaatgccgatgctaatgcagagccaaggaagcattgctgtcgtctcctcgg tggctgggaaaataacttatcctctgattgctccctattctgcaagcaagttcgctctggatggattcttctcgacccttaggtcagagtttttagtgaacaaagt caatgtgtcgatcactctgtgcatccttggcttgatagacacagagacagccataaaggcaacttcggggatatatttaggacctgcatctccaaaggag gagtgtgctctggagatcatcaaagggacagctctgcgtcaagacgaaatgtactatgtcggctcacgctgggtcccatacctgctaggaaatccagga agaaagatcatggaatttctctcagcagcagaatataactgggacaatgtattaagcaacgagtgaCTCG (SEQ ID NO:5) Sequence 6: Amino acid sequence of guinea pig 11 ?HSD1 in pET28a vector for soluble expression in E. coli. Characters in the upper case indicate amino acids introduced by the pET28a vector. Characters in the lower case indicate the actual amino acid sequence of guinea pig 11 7HSD1 sequence corresponding to N24-E293. The amino acids introduced by the vector contain a His-6 tag, a thrombin cleavage sequence and a T7 tag. The His-6 tag was removed during purification process through thrombin digestion, the sequence of the protein that eventually went into crystallization starts at "GSHMASMTGGQQMGRGSnekfrpem" and ends at "nvlsne".

MGSSHHHHHHSSGLVPRGSHMASMTGGQQMGRGSnekfrpemlqgkkvivtgaskgigreiayhlakmgahvvvtarskeal qkvvarclelgaasahyiagsmedmtfaeefvaeagnlmggldmlilnhvlynrltffhgeidnvrksmevnfhsfwlsvaampmlmqsqgsiavvs svagkitypliapysaskfaldgffstlrseflvnkvnvsitlcilglidtetaikatsgiylgpaspkeecaleiikgtalrqdemyyvgsrwvpyllgnpgrkime flsaaeynwdnvlsne (SEQ ID NO:6)

Sequence 7: Amino acid sequence of the guinea pigl 1 ?HSD1 (Form 1) (N24-E293) protein used for crystallization experiments (as derived from SEQ ID NO:6).

GSHMASMTGGQQMGRGSnekfrpemlqgkkvivtgaskgigreiayhlakmgahvvvtarskealqkvvarclelgaasahyiagsmed mtfaeefvaeagnlmggldmlilnhvlynrltffhgeidnvrksmevnfhsfvvlsvaampmlmqsqgsiavvssvagkitypliapysaskfaldgffstl rseflvnkvnvsitlcilglidtetaikatsgiylgpaspkeecaleiikgtalrqdemyyvgsrwvpyllgnpgrkimeflsaaeynwdnvlsne (SEQ ID NO:7)

Sequence 8: Amino acid sequence of the guinea pigl 1 ?HSD1 (Form 2) N24-A300 protein used for crystallization experiments. GSHMASMTGGQQMGRGSnekfrpemlqgkkvivtgaskgigreiayhlakmgahvvvtarskealqkvvarclelgaasahyiagsmed mtfaeefvaeagnlmggldmlilnhvlynrltffhgeidnvrksmevnfhsfvvlsvaampmlmqsqgsiavvssvagkitypliapysaskfaldgffstl rseflvnkvnvsitlcilglidtetaikatsgiylgpaspkeecaleiikgtalrqdemyyvgsrwvpyllgnpgrkimeflsaaeynwdnvlsneklygrwa (SEQ ID NO:8)

Sequence 9: Amino acid sequence of a human 11 ?HSD1 (Mutant A) protein used for crystallization studies.

Human 11jffHSD1 (Mutant A)(F278E)

NEEFRPEMLQGKKVIVTGASKGIGREMAYHLAKMGAH

VVVTARSKETLQKVVSHCLELGAASAHYIAGTMEDMTFAEQFVAQAGKLMGGLDMLILNH

ITNTSLNLFHDDIHHVRKSMEVNFLSYVVLTVAALPMLKQSNGSIVVVSSLAGKVAYPMV AAYSASKFALDGFFSSIRKEYSVSRVNVSITLCVLGLIDTETAMKAVSGIVHMQAAPKEE

CALEIIKGGALRQEEVYYDSSLWTTLLIRNPCRKILEELYSTSYNMDRFINK (SEQ ID NO:9)

Sequence 10: DNA sequence of another human 11βHSD1 (Mutant B) (L262R, F278E) in pET28a(+)

ATGGGCAGCAGCCATCATCATCATCATCACAGCAGCGGCCTGGTGCCGCGCGGCAGCCATATGGCTA GCATGACTGGTGGACAGCAAATGGGTCGCGGATCCAACGAGGAATTCAGACCAGAGATGCTCCAAGG AAAGAAAGTGATTGTCACAGGGGCCAGCAAAGGGATCGGAAGAGAGATGGCTTATCATCTGGCGAAG ATGGGAGCCCATGTGGTGGTGACAGCGAGGTCAAAAGAAACTCTACAGAAGGTGGTATCCCACTGCC TGGAGCTTGGAGCAGCCTCAGCACACTACATTGCTGGCACCATGGAAGACATGACCTTCGCAGAGCA ATTTGTTGCCCAAGCAGGAAAGCTCATGGGAGGACTAGACATGCTCATTCTCAACCACATCACCAACA CTTCTTTGAATC l l l l l CATGATGATATTCACCATGTGCGCAAAAGCATGGAAGTCAACTTCCTCAGTTA CGTGGTCCTGACTGTAGCTGCCTTGCCCATGCTGAAGCAGAGCAATGGAAGCATTGTTGTCGTCTCCT CTCTGGCTGGGAAAGTGGCTTATCCAATGGTTGCTGCCTATTCTGCAAGCAAGTTTGCTTTGGATGGG TTCTTCTCCTCCATCAGAAAGGAATATTCAGTGTCCAGGGTCAATGTATCAATCACTCTCTGTGTTCTTG GCCTCATAGACACAGAAACAGCCATGAAGGCAGTTTCTGGGATAGTCCATATGCAAGCAGCTCCAAAG GAGGAATGTGCCCTGGAGATCATCAAAGGGGGAGCTCTGCGCCAAGAAGAAGTGTATTATGACAGCT CACGTTGGACCACTCTTCTGATCAGAAATCCATGCAGGAAGATCCTGGAAGAACTCTACTCAACGAGC TATAATATGGACAGATTCATAAACAAG

(SEQ ID NO: 10)

Sequences 11-14: Primers for the mutations

Sequence 11

L262R-F: GTATTATGACAGCTCACGTTGGACCACTCTTCTG (SEQ ID NO: 11) Sequence 12

L262R-R: CAGAAGAGTGGTCCAACGTGAGCTGTCATAATAC (SEQ ID NO: 12)

Sequence 13

F278E-F: AGGAAGATCCTGGAAGAACTCTACTCAACGAGC (SEQ ID NO: 13)

Sequence 14 F278E-R: GCTCGTTGAGTAGAGTTCTTCCAGGATCTTCCT (SEQ ID NO: 14)

Sequence 15

Amino acid sequence of human 11/JHSD1 (Mutant B) (L262R, F278E) in pET28a(+)

MGSSHHHHHHSSGLVPRGSHMASMTGGQQMGRGSNEEFRPEMLQGKKVIVTGASKGIGREMAYHLAKM GAHVWTARSKETLQKVVSHCLELGAASAHYIAGTMEDMTFAEQFVAQAGKLMGGLDMLILNHITNTSLNLF HDDIHHVRKSMEVNFLSYVVLTVAALPMLKQSNGSIVVVSSLAGKVAYPMVAAYSASKFALDGFFSSIRKEY SVSRVNVSITLCVLGLIDTETAMKAVSGIVHMQAAPKEECALEIIKGGALRQEEVYYDSSRWTTLLIRNPCRKI LEELYSTSYNMDRFINK (SEQ ID NO: 15)

Sequence 16: DNA sequence of human 11beta HSD1 (Mutant C) (M179L, L262R, F278E, M286W) in pET28a(+) ATGGGCAGCAGCCATCATCATCATCATCACAGCAGCGGCCTGGTGCCGCGCGGCAGCCATATGGCTA GCATGACTGGTGGACAGCAAATGGGTCGCGGATCCAACGAGGAATTCAGACCAGAGATGCTCCAAGG AAAGAAAGTGATTGTCACAGGGGCCAGCAAAGGGATCGGAAGAGAGATGGCTTATCATCTGGCGAAG ATGGGAGCCCATGTGGTGGTGACAGCGAGGTCAAAAGAAACTCTACAGAAGGTGGTATCCCACTGCC TGGAGCTTGGAGCAGCCTCAGCACACTACATTGCTGGCACCATGGAAGACATGACCTTCGCAGAGCA ATTTGTTGCCCAAGCAGGAAAGCTCATGGGAGGACTAGACATGCTCATTCTCAACCACATCACCAACA CTTCTTTGAATC l l l l l CATGATGATATTCACCATGTGCGCAAAAGCATGGAAGTCAACTTCCTCAGTTA CGTGGTCCTGACTGTAGCTGCCTTGCCCATGCTGAAGCAGAGCAATGGAAGCATTGTTGTCGTCTCCT CTCTGGCTGGGAAAGTGGCTTATCCACTGGTTGCTGCCTATTCTGCAAGCAAGTTTGCTTTGGATGGG TTCTTCTCCTCCATCAGAAAGGAATATTCAGTGTCCAGGGTCAATGTATCAATCACTCTCTGTGTTCTTG GCCTCATAGACACAGAAACAGCCATGAAGGCAGTTTCTGGGATAGTCCATATGCAAGCAGCTCCAAAG GAGGAATGTGCCCTGGAGATCATCAAAGGGGGAGCTCTGCGCCAAGAAGAAGTGTATTATGACAGCT CACGTTGGACCACTCTTCTGATCAGAAATCCATGCAGGAAGATCCTGGAAGAACTCTACTCAACGAGC TATAATTGGGACAGATTCATAAACAAG (SEQ ID NO: 16)

Sequences 17-24: Primers for the Mutations

Sequence 17: M179L-F: AAAGTGGCTTATCCACTGGTTGCTGCCTATTCT (SEQ ID NO: 17)

Sequence 18:

M179L-R: AGAATAGGCAGCAACCAGTGGATAAGCCAC (SEQ ID NO: 18)

Sequence 19:

L262R-F: GTATTATGACAGCTCACGTTGGACCACTCTTCTG (SEQ ID NO: 19) Sequence 20:

L262R-R: CAGAAGAGTGGTCCAACGTGAGCTGTCATAATAC (SEQ ID NO: 20)

Sequence 21:

F278E-F: AGGAAGATCCTGGAAGAACTCTACTCAACGAGC (SEQ ID NO: 21)

Sequence 22: F278E-R: GCTCGTTGAGTAGAGTTCTTCCAGGATCTTCCT (SEQ ID NO: 22)

Sequence 23:

M286W-F: CTCAACGAGCTATAATTGGGACAGATTCATAAAC (SEQ ID NO: 23)

Sequence 24:

M286W-R: GTTTATGAATCTGTCCCAATTATAGCTCGTTGAG (SEQ ID NO: 24) Sequence 25:

Amino acid sequence of human 11 HSD1 (Mutant C) (M179L, L262R, F278E, M286W) in pET28a(+)

MGSSHHHHHHSSGLVPRGSHMASMTGGQQMGRGSNEEFRPEMLQGKKVIVTGASKGIGREMAYHLAKM GAHVWTARSKETLQKVVSHCLELGAASAHYIAGTMEDMTFAEQFVAQAGKLMGGLDMLILNHITNTSLNLF HDDIHHVRKSMEVNFLSYVVLTVAALPMLKQSNGSIVVVSSLAGKVAYPLVAAYSASKFALDGFFSSIRKEY SVSRVNVSITLCVLGLIDTETAMKAVSGIVHMQAAPKEECALEIIKGGALRQEEVYYDSSRWTTLLIRNPCRKI LEELYSTSYNWDRFINK (SEQ ID NO: 25)

Example 2 EXPRESSION AND PURIFICATION OF GUINEA PIG 11 HSD1 : Two different guinea pig constructs have been expressed and crystallized. A first construct of the present invention consists of residues N24-E293 from the guinea pig along with additional amino acids at the N-terminus as shown in SEQ ID NOS: 6 and 7: SEQ ID NO: 7 is derived from SEQ ID NO: 6 via thrombin digestion and contains a shorter N-terminal region than SEQ ID NO: 6. SEQ ID NO: 7 led to the first guinea pig apo crystal and some cocrystals. The second guinea pig sequence was introduced into the same vector as SEQ ID NO: 6, but this construct consists of residues N24-A300 (i.e. an additional seven residues C-terminal to the construct used in SEQ ID NO: 7). In other words, the expressed sequence is identical to SEQ ID NO: 7 but contains the following seven additional amino acids at the C-terminus "klygrwa". Just as with the first construct, a thrombin digestion was performed and led to a derivative that is identical to SEQ ID NO: 7 but contains the seven additional amino acids at the C-terminus ("klygrwa"). This thrombin digested construct led to the second form of the guinea pig apo crystal as well as cocrystals including the 18 β glycyrrhetinic acid complex structure. E. coli B621(DE3) harboring the pET28a plasmid containing the 11 ?HSD1 gene (SEQ ID NO:5) was grown in terrific broth supplemented with Kanamycin. The culture was grown in a 10-6 fermentor at 37°C until it reached an optical density of about 3.0. Cells were induced with 0.75uM 1 pTG for 16-18 hours at 18°C and harvested by centrifugation. E. coli cell paste with expressed guinea pig 11 JHSD1 was resuspended in (50ml per liter cell paste) ice-cold lysis buffer (50mM Tris pH 8.5, 500mM NaCl, 5mM Tris (2-carboxyethyl) phosphine hydrocloride [TCEP] (Sigma), 100mM imidazole, 0.1% dodecyl-B-maltoside (DDM), and 1 tablet of Roche protease inhibitor per 50mL of total buffer volume) and lysed by 3 passages through a pre-chilled microfluidizer (M110L, Microfluidics International Corp., Needham, MA) at 18 kPSI chamber pressure. Lysate is then centrifuged overnight at 41 ,000g in 4°C temperature. Hereon, every purification step is conducted at 4°C. Next, the supernatant is decanted, filtered (0.45 micron Nalgene filter), and passed through a nickel chelating affinity matrix (Amersham). After lysate is loaded onto the column, it is first washed with lysis buffer, then with 50mM Tris pH 8.5, 500mM NaCl, 5mM TCEP, 100mM imidazole, 0.01% DDM, 2% glycerol, and finally target protein is eluted with 50mM Tris pH 8.5, 500mM NaCl, 5mM TCEP, 175mM imidazole, 0.01 % DDM, 2% glycerol. The eluted 11βHSD1 peak is pooled and concentrated using an Amicon Bioseparations stirred cell (Millipore) with a 10K cutoff Biomax PBGC membrane (Millipore). Upon concentration, the protein solution is immediately desalted using a HiPrep 26/10 desalting column into the no salt buffer (50mM Tris pH 8.5, 500mM NaCl, 5mM TCEP, 0.01 % DDM, 5% glycerol). Next, thrombin is added to the desalted protein at 1 mg/ml of 11βHSD1 and 20 units of thrombin per mg of 11/JHSD1 to remove the histidine tag from the target protein. The thrombin digest is allowed to proceed at 4°C overnight with constant mild shaking. After digestion the protein solution is passed through a second Amersham HiTrap nickel chelating affinity column to remove any undigested protein. After protein is loaded onto the column, it is first washed with 50mM Tris pH 8.5, 500mM NaCl, 5mM TCEP, 0.01% DDM, 5% glycerol and the digested protein (non-specific binding to the column) is eluted with 50mM Tris pH 8.5, 500mM NaCl, 5mM TCEP, 0.01 % DDM, 5% glycerol, 50mM imidazole.. Finally, the eluted peak is pooled, concentrated, and passed over an Amersham superdex 200 gel filtration column. The buffer for this column, which is also the final protein buffer, is 25mM Tris pH 8.5, 100mM NaCl, and 5mM TCEP, 5% glycerol. Crystallization of guinea pig 11 HSD1 apo protein of guinea pig 11βHSD1 :

Crystals of guinea pig 11/?HSD1 apo protein (SEQ ID NO: 7) were grown with vapor diffusion. Crystals in long rod form (0.05 X 0.1 X 0.4 mm) appeared after 1-3 days when the protein (8 mg/ml in 25 mM Tris pH=8.5, 100 mM NaCl, 5% Glycerol, 5 mM NADP⁺ and 5 mM TECP) was mixed with an equal volume of reservoir (100mM Hepes PH=7.8, 35% PPG, 160 M NaCl, 5 mM TECP, and 0.25% v/v Dichloromethane) at 5 °C.

Example 3

Guinea Pig Crystal 11 JHSD1 , Form 1 Crystals were transferred to a cryoprotectant solution (20mM Hepes PH=7.8, 44% PPG, 50 mM NaCl, 5 mM TECP and 5 mM NADP⁺,)_t and then flash-frozen by quickly dipping into liquid nitrogen. A full data set was collected from one crystal frozen in this manner at APS 17ID. Data were processed using the HKL2000 suite of software (Otwinowski & Minor, Methods Enzymol. 276(Macromolecular Crystallography, Part A: 307-26 (1997)). Data collection statistics are summarized in Table 10.

Table 10 -Data statistics for the coordinates of FIG. 6

Resolution range 50.0-2.07 A Number of observations Unique 59400 Redundancy 4

Completeness(%) 99.6(99.8)¹ l/σ(l) 17.9(3.7)¹ r^s m 0.073(0.35) 1,2

¹ Numbers in parentheses refer to the highest resolution range (2.14-2.07 ) R_sym = Σ (l-<l>)/∑<l> The guinea pig crystals belong to space group P21212 with unit cell dimensions a=171.080 A, b=62.831 A, c=89.646 A, a=β=y=90.0°. They contain 3 molecules of the polypeptide, and 3 molecules of the co-factor NADP⁺ per asymmetric unit. The NADP⁺ molecules are tightly bound to the proteins. Of the 3 molecules in the asymmetric unit, two form a dimer, and the third one forms the same dimer with a symmetry related molecule (FIG. 1). The structure was solved by the method of molecular replacement, using the program MOLREP in the CCP4 package. The search model consisted of the Rossmann fold regions of 5 SCD (short-chain dehydrogenase) superimposed on top of each other. The 5 SCDs are: 3-σ, 20-β-hydroxysteroid dehydrogenase(PDB entry 1 HDC), ?-Keto Acyl Carrier Protein Reductase(PDB entry 1EDO), Glucose Dehydrogenase (Bacillus megaterium)(PDB entry 1GCO), Meso-2,3-Butanediol Dehydrogenase (Klebsiella pneumoniae) (PDB entry 1 GEG), and Tropinone Reductase-ll (PDB entry 2AE2). A clear solution to the rotation and translation function searches was found using diffraction data limited to 4 A resolution. A homology model of guinea pig 11βHSD1 (containing the Rossmann fold region based on 3-σ, 20- β-hydroxysteroid dehydrogenase(PDB entry 1 HDC)) was then positioned according to the top rotation/translation search, and subjected to refinement, and a combination of automatic and manual refitting. Automated model rebuilding was carried out using the program SOLVE/RESOLVE and the program ArpWarp in combination with Refmac (Murshudov et al., Acta Cryst. D53:240-55 (1997)), and manual fitting used the program O. Refinement in CNX was carried out using all data in the resolution range 20.0 - 2.07A. The R-factor for the current model is 0.21 (free R-factor, 5 % of the data, 0.24). The refinement statistics are summarized in Table 11.

Table 11. Refinement Statistics

Nr. Of reflections used (%) 56344 (85.1 %)

Nr. Of reflections used for R_free 3007( 4.5%)

Rwork/Rfree 0.209/0.238³

Number of atoms 2,932 ' ³ R = ∑||F_obs| - /ciF_calc||/Σ|F_obs|

The current model contains three identical polypeptide chains of 11 ?HSD1. Each of the polypeptide chain contains 263 out of 287 ammo acid residues calculated on the basis of the construct (17 amino acid residues introduced by the vector and about 270 amino acid from 11 ?HSD1). No interpretable electron density is observed for the 17 residues comes from the pET28a vector, Asn24-Glu25, and Val289-Glu293. In addition, the model contains three molecules of tightly bound NADP⁺ and 179 water molecules.

Guinea Pig Crystal 11 ?HSD1 , Form 2

Crystals of guinea pig 11 βHSD1 apo protein (SEQ ID NO: 8) were grown by vapor diffusion.

Crystals appeared from overnight to 1 week. Crystals are tetrahedral bipyrimidal, approximately 0.1 x 0.1 x 0.1 mm in size. The protein (6 mg/ml in 25mM TRIS pH 8.0, 50mM NaCl, 5mM TCEP, 5% glycerol, 1 mM NADP was mixed with an equal volume of reservoir solution (100mM Ammonium Sulfate, 100mM Sodium Citrate, pH 5.8, 22 - 25% PEG 6000, 15-20% glycerol) at 22°C.

Cryoprotection:

The crystals were transferred for 1-5 seconds to a solution of 20% glycerol and 80% reservoir solution (above) and flash frozen in a stream of nitrogen gas at -170°C. Data sets were collected with a rotating anode X-ray generator and MAR 345 image plate detector to 2.40A. Data were processed using the HKL2000 suite of software (Otwinowski & Minor, Methods Enzymology 276, Macromolecular Crystallography Part A:307-26(1997)). Data collection statistics are summarized in Tables 12-13.

Table 12. DATA STATISTICS - Guinea Pig 11 HSD1 crystal, Form 2 Table 11 Resolution Range: 50.0 - 2.40A Number of Unique observations: 45005 ,

Redundancy 3.8

Completeness(%) 98.4(88.5) ¹ l/σ(l) 9.0(1.50) ¹ Rsym 0.138(0.536) ¹'²

1 Numbers in parenthesis refer to the highest resolution range (2.49-2.40A)

2 Rsym = ∑(l-<l>)/ ∑<l>

The crystal belong to space group P212121 with unit cell dimensions a= 77.756 b=83.145 c= 179.295 a =β=γ 90.0°. They contain 4 molecules of the polypeptide and 4 molecules of the co-factor NADP+ per asymmetric unit. The 4 molecules form 2 sets of dimmers, with 2 dimers in the asymmetric unit.

The structure was solved by the method of molecular replacement, using the program AMORE in the CCP4 program package. The search model was the previously solved guinea pig 11 β HSD structure from crystal form A. The structure was refined with CNX and manual fitting using the program Xfit. The refinement statistics for the partially refined model are: Table 13. Refinement statistics for Guinea Pig 11 ?HSD1 crystal, Form 2

Nr reflections used (%) 39274 (84.8%)

Nr reflections used for Rfree 2041 (4.4%)

Rwork/ Rfree 0.294/0.351

R= Σ||Fobs|-k|Fcalc||/ Σ|Fobs| The current molecule contains 4 identical polypeptide chains with no co-factors (NADP+) or waters. No interpretable electron density is seen for residues before Lys26 or after Asn288.

Example 4

Cloning, Sub-Cloning and Purification of Human 11 ?HSD1

Three improved human mutants were designed to improve the solubility of the wild type or N24 C272S mutant that were not suitable for crystallization. The three human mutants Were designed to have more soluble residues on the protein surface and were designed using the guinea pig structure. Each mutant sequence starts at N24 and goes to K292. They are mutant A (F278E), mutant B (L262R, F278E) and mutant C (M178L, L262R, F278E, M286W). The vector used for expression and the purification process used for all human mutants was identical to that used for the guinea pig, i.e. each was first expressed using a His-6 tag (as shown in SEQ ID NO: 15 for mutant B and SEQ ID NO: 25 for mutant C). The construct used for crystallization and also for activity characterization was then thrombin digested, so the initial amino acids "MGSSHHHHHHSSGLVPR" were removed, similar to the difference between SEQ ID NOS: 6 and 7. The activity and fraction active for these mutants are (where larger kcat/Km and higher %active is better) are shown above in Table 8: Human 11 ?HSD1 and mutants thereof were cloned into the same expression vector pET28a(+) as guinea pig 11 HSD1. Both proteins have very high level expression in the pET28a(+). Expression condition is also the same as for guinea pig HSD1.

HUMAN Mutant B Human 11β HSD crystals (SEQ ID NO: 15) were grown by vapor diffusion. (7mg/ml in 50mM TRIS pH 8.0, 100mM NaCl, 20% glycerol 5-10 mM TCEP) was mixed with an equal volume of reservoir ( 100mM MES pH 6.5, 23- 30% MPEG 5000, 200mM Ammonium sulfate, 20% glycerol) The crystals grew as rods about 0.2mm long in 3 -10 days.

Cryprotection: The crystals were briefly placed in the reservoir solution (1-5 seconds) and flash frozen in a stream of nitrogen gas at -170°C.

Data sets were collected with a rotating anode X-ray generator and MAR 345 image plate detector to 3.10A. Data were processed using the HKL2000 suite of software (Otwinowski & Minor, Methods Enzymology 276 Macromolecular Crystallography Part A:307-26(1997)). Data collection statistics are summarized in Tables 14-15.

DATA STATISTICS TABLE 14 Human Mutant B crystals

Resolution Range: 50.0 - 3.10A

Number of Unique observations: 21510

Redundancy 5.1 Completeness(%) 99.8(98.0) ¹ l/σ(l) 11.8(2.45) ¹

Rsym 0.129(0.504) ¹'²

¹ Numbers in parenthesis refer to the highest resolution range (2.49-2.40A)

²Rsym = Σ(l-<l>)/ Σ<l> The structure was solved by the method of molecular replacement, using the program AMORE in the CCP4 program package. The search model was the previously solved guinea pig 11β HSD structure from crystal Form B. The structure was refined with CNX and Refmac (Murshudov et al., Acta Cryst. D53:241-55(1997)) with manual fitting using the program Xfit. The refinement statistics for the refined model are:

Table 15. Refinement statistics for Human Mutant A crystals of FIG. 9 '

Nr reflections used (%) 20287 (94.8%)

Nr reflections used for Rfree 1115 (5.0%)

Rwork/ Rfree 0.214/0.288 R= Σ||Fobs|-k|Fcalc||/ Σ|Fobs|

Description of the structure

Overall, the structure is very similar to the guinea pig 11 β HSD1 structures with an RMSD of about 1 A. The model contains 4 polypeptide chains of human and 4 NADP+ molecules and no waters. Example 5 Human 11 ?HSD1 was overexpressed in BL21(DE3) Ecoli cells. 20 g of the cell pellets expressing human 11#HSD1 was resuspended in 100 ml of lysis buffer (50 mM Tris-HCl, pH 8.0, 0.3 M NaCl, 20% glycerol, 0.4% beta-DDM, 5 mM β-mercaptoethanol) supplemented with 2 tablets of EDTA-free protease inhibitor cocktail (Roche Applied Science). The suspension was passed through the microfluidizer at 100 PSI twice. The cell lysate was clarified by centrifuging at 40,000 rpm for 45 min in an ultracentrifuge (Beckman Coulter Inc.). The supernatant was saved. The supernatant was loaded onto a 20 ml Ni-NTA column (Qiagen Inc.) pre-equilibrated with the lysis buffer containing 20 mM imidazole. After the sample was loaded onto the column, the column was washed with 100 ml of lysis buffer containing 20 mM imidazole. Then, the protein was eluted with 200 ml of linear gradient formed from 100% buffer A (50 mM Tris-HCl, pH 8.0, 0.3 M NaCl, 20% glycerol, 0.1 % beta- DDM, 40 mM imidazole, 5 mM ?-mercaptoethanol) to 100% buffer B (50 mM Tris-HCl, pH 8.0, 0.15 M NaCl, 10% glycerol, 0.1% ?-DDM, 300 mM imidazole, 5 mM ?-mercaptoethanol). The elution profile was monitored with UV absorbance at 280 nm. Factions containing 11 ?HSD1 were identified by running SDS- PAGE (12%, Invifrogen Inc.) and staining with Coomassie Blue R-250 (Bio-Rad Inc.). The initial crystallization protocol for guinea pig 11 βHSDI and 18β glycyrrhetinic acid cocrystal structure was the same as for guinea pig 11 βHSDI apo crystal Form 2. Following the generation of guinea pig 11 βHSDI apo crystal form 2, 1 l inhibitor 18 β glycyrrhetinic acid (Aldrich Chemical, CAS #471-53-4) at 100mM in DMSO was added to drops with crystals. Final concentration of inhibitor is 5mM for 2μ\ drops. Crystals were soaked for up to a week and frozen as above for GP 11 βHSD crystal form 2. Data were collected at ALS beamline 5.0.2 and processed as with the guinea pig 11 βHSDI apo crystal form 2 with HKL2000 (Otwinowski & Minor, Methods Enzymology 276, Macromolecular Crystallography Part A:307- 26(1997)).

DATA STATISTICS - guinea pig 11 βHSDI crystal Form 2 complexed with glycyrrhetinic acid

Table 16. Resolution Range: 50.0 - 2.00A

Number of Unique observations: 76351

Redundancy 2.8

Completeness(%) 96.0(97.7) ¹ l/σ(l) 10.9(1.3) ¹ Rsym 0.085(0.656) ¹'² ¹ Numbers in parenthesis refer to the highest resolution range (2.07-2.00A)

² Rsym = ∑(l-<l>)/ ∑<l>

The crystal belongs to space group P212121 with unit cell dimensions a= 77.888 b=83.129 c= 179.437 a -β-y 90.0°. They contain 4 molecules of the polypeptide and 4 molecules of the co-factor NADP+ per asymmetric unit. The 4 molecules form 2 sets of dimers, with 2 dimers in the asymmetric unit.

The structure was solved by the method of molecular replacement, using the program REFMAC in the CCP4 program package. The search model was the previously solved guinea pig 11 βHSDI structure crystal Form 2. The structure was refined with REFMAC and manual fitting using the program Xfit. The refinement statistics for the partially refined model are: Table 17. Refinement statistics for guinea pig 11 βHSDI crystal Form 2 with 18β glycyrrhetinic acid

Nr reflections used (%) 72452 (95.8%)

Nr reflections used for Rfree 3845 (5.3%)

Rwork/ Rfree 0.209/0.260

R= Σ||Fobs|-k|Fcalc||/ Σ|Fobs| The molecule contains 4 identical polypeptide chains with the co-factor NADP+ and inhibitor glycyrrhetinic acid in each chain and 244 waters. No interpretable electron density is seen for residues before Lys26 or after Asn288. The glycyrrhetinic acid is in the active site of the molecule. Equivalents While specific embodiments of the subject invention have been discussed, the above specification is illustrative and not restrictive. Many variations of the invention will become apparent to those skilled in the art upon review of this specification. The appended claims should be interpreted by reference to the claims, along with their full scope of equivalents, and the specification, along with such variations. All publications and patents mentioned herein are hereby incorporated by reference in their entireties. In case of conflict any definitions herein will control.

Claims

CLAIMS f

What is claimed is: 1. A crystalline composition of 11 beta Hydroxysteroid Dehydrogenase Type 1 (11,ffHSD1 ). 2. The 11βHSD1 crystal of claim 1 which is derived from a mammal and preferably a human. 3. The 11/iHSD1 crystal of claim 1 in complex with a ligand. 4. The 11j5HSD1 crystal of claim 1 comprising an 11 ?HSD1 amino acid sequence of one of SEQ ID NO:7; SEQ ID NO:8; SEQ ID NO: 9; SEQ ID NO: 15 or SEQ ID NO: 25 or a homologue, functional fragment, variant, analogue or derivative thereof. 5. The 11βHSD1 crystal of claim 4 including at least one additional amino acid substitution to said amino acid sequence. 6. The 11 JHSD1 crystal of Claim 1 , which is characterized by a set of structural coordinates that are substantially similar to the set of structural coordinates of one of FIG. 6, FIG. 9, FIG. 10 or FIG. 11. 7. The crystal of claim 4, wherein the homologue, functional fragment, variant, analogue or derivative thereof has a protein backbone comprising the atomic coordinates, or portions thereof, that are within a root mean square of about +/- 2.0, 1.7, 1.5, 1.2, 1.0, 0.7, 0.5, or even 0.2 A of the atomic coordinates, or portions thereof, listed in one of FIG.6, FIG. 9 or FIG. 10. 8. A polypeptide comprising the amino acid sequence set forth in SEQ ID NO:7 or a homologue, functional fragment, variant, analogue or derivative thereof, wherein the molecules are arranged in a crystalline manner belonging to space group P21212 with unit cell dimensions of about a=171.08 A, b=62.83 A, c=89.65 A, and a=β=γ=90.Q°, and which effectively diffracts X-rays for determination of the atomic coordinates of 11 ?HSD1 polypeptide to a resolution of about 2.1 A. 9. A polypeptide comprising the amino acid sequence set forth in SEQ ID NO:8 or a homologue, functional fragment, variant, analogue or derivative thereof, wherein the molecules are arranged in a crystalline manner belonging to space group P212121 with unit cell dimensions of about a=77.8 A, b=83.1 A, c=179.3 A, and a=β=γ=90.0°, and which effectively diffracts X-rays for determination of the atomic coordinates of 11/JHSD1 polypeptide to a resolution of about 2.0 A. 10. A polypeptide comprising the amino acid sequence set forth in SEQ ID NO:8 or a homologue, functional fragment, variant, analogue or derivative thereof, wherein the molecules are arranged in a crystalline manner in complex with a ligand belonging to space group P212121 with unit cell dimensions of about a=77.8 A, b=83.1 A, c=179.4 A, and a=β=γ=9Q.Q°, and which effectively diffracts X-rays for determination of the atomic coordinates of 11/?HSD1 polypeptide to a resolution of about 2.0 A. 11. A computer for producing a three-dimensional representation of a polypeptide with an 11 HSD1 amino acid sequence or a homologue, functional fragment, variant, analogue or derivative thereof comprising: a computer-readable data storage medium comprising a data storage material encoded with computer-readable data, wherein said data comprises the structure coordinates that are substantially similar to the set of structural coordinates of one of FIG. 6, FIG. 9 or FIG. 10, or portions thereof; a working memory for storing instructions for processing said computer-readable data; a central-processing unit coupled to said working memory and to said computer-readable data storage medium for processing said computer-machine readable data into said three- dimensional representation; and a display coupled to said central-processing unit for displaying said representation. 12. A method for identifying ligands for 11βHSD1 , or homologues, analogues or variants thereof, comprising the steps of: displaying three dimensional structure of 11βHSD1 enzyme, or portions thereof, as defined by atomic coordinates in one of FIG. 6, FIG. 9 or FIG. 10 on a computer display screen; optionally replacing one or more 11 ?HSD1 enzyme amino acid residues listed in one of SEQ ID NO: 7, SEQ ID NO: 8 or SEQ ID NO: 15, in said three-dimensional structure with a different naturally occurring amino acid or an unnatural amino acid; employing said three-dimensional structure to design or select said ligand;contacting said ligand with 11 ?HSD1 , or variant thereof, in the presence of one or more substrates; and measuring the ability of said ligand to modulate the activity 11 ?HSD1. 13. The method of claim 13 further comprising the steps of: computationally modifying the structure of the ligand; and computationally determining the fit of the modified ligand with the three-dimensional coordinates of 11/?HSD1 set forth in one of FIG. 6, FIG. 9 or FIG. 10 or portions thereof. 14. A human 11 ?HSD1 polypeptide comprising at least one amino acid substitution selected from amino acids 179; 262; 278 and/or 286. \