NZ719338B2 - Modified kz144 endolysin sequence - Google Patents

Abstract

The present invention relates to polypeptides comprising an amino acid sequence exhibiting at least about 90% sequence identity with the sequence of SEQ ID NO: 1. Said polypeptides preferably degrade the peptidoglycan of Gram-negative bacteria, in particular of Pseudomonas and/or Campylobacter bacteria. In addition, the present invention relates to nucleic acids encoding such polypeptides, vectors comprising such nucleic acids, and corresponding host cells. Finally, the present invention relates to compositions comprising such polypeptides, nucleic acids, vectors, and/or host cells according to the present invention. In particular, the present invention relates to a modified KZ144 endolysin sequence (SEQ ID NO: 1) which have heat stabilizing mutations. The heat stabilizing mutations are selected from at least one of (i) X23S (ii) X14S and X50S (iii) X82I (iv) X122M and X160T (v) X206V or (vi) X232T. ria. In addition, the present invention relates to nucleic acids encoding such polypeptides, vectors comprising such nucleic acids, and corresponding host cells. Finally, the present invention relates to compositions comprising such polypeptides, nucleic acids, vectors, and/or host cells according to the present invention. In particular, the present invention relates to a modified KZ144 endolysin sequence (SEQ ID NO: 1) which have heat stabilizing mutations. The heat stabilizing mutations are selected from at least one of (i) X23S (ii) X14S and X50S (iii) X82I (iv) X122M and X160T (v) X206V or (vi) X232T.

Description

Modified KZ144 endolysin sequence The present ion relates to polypeptides comprising an amino acid sequence exhibiting at least about 90% ce identity with the sequence of SEQ ID NO: 1. Said polypeptides preferably e the peptidoglycan of Gram-negative bacteria, in particular of monas and/0r Campylobacter bacteria. In on, the present invention relates to nucleic acids encoding such polypeptides, vectors sing such nucleic acids, and corresponding host cells. Finally, the present invention relates to compositions sing such polypeptides, nucleic acids, vectors, and/or host cells according to the present invention.

The giant, lytic Myoviridae bacteriophage ¢KZ (280 334 bp) infects Pseudomonas aeruginosa, an important unistic nosocomial pathogen ant to many commonly used antibiotics, and is therefore the cause of considerable concern in hospital environments.

In 2007, Briers et al. (Molecular Microbiology (2007) 65(5), 1334—1344) sequenced the genome of said iophage and identified the endolysin K2144, a highly lytic peptidoglycan hydrolase. In said endolysin as enzymatic element has been proposed for use in degrading the cell wall of Gram—negative bacteria.

While said endolysin and fusion proteins are effective in general, it turned out, that for some technical applications the endolysin polypeptide exhibits suboptimal characteristics, in ular in terms of stability and processing. Thus, there was a need in the art for a further endolysin enzyme, which exhibits preferably improved characteristics in this respect. The m of the present invention was thus to provide such polypeptide.

The problem is solved by the subject-matter as set forth in the appended claims.

In the following a brief description of the appended figures will be given. The figures are intended to illustrate the present ion in more detail. However, they are not intended to limit the subject matter of the invention to any extent.

Fig. 1: illustrates: SEQ ID NO: 1, SEQ ID NO: 2 K2144 endolysin without N—terminal methionine, SEQ ID NO: 3 K2144 endolysin without N—terminal methionine and with selenomethionine residues instead of methionine residues, SEQ ID NO: K2144 endolysin with E115A mutation without N—terminal methionine, and SEQ ID NO: K2144 endolysin.

Fig. 2: illustrates: SEQ ID NO: 136 Fusion protein of SMAP—29 (underlined with solid line; SEQ ID NO: 76), ed K2144 without N—terminal methionine and with C14S and C50S lined with semi—dotted/semi— solid line; SEQ ID NO: 28) and His—tag (underlined with dotted line; SEQ ID NO: 135).

SEQ ID NO: 137 Fusion protein of SMAP—29 (underlined with solid line; SEQ ID NO: 76), modified K2144 without N—terminal methionine and with T821, A206V and S232T (underlined with semi— dotted/semi—solid line; SEQ ID NO: 29) and His—tag (underlined with dotted line; SEQ ID NO: 135).

SEQ ID NO: 138 Fusion protein of SMAP—29 (underlined with solid line; SEQ ID NO: 76), ed K2144 without N—terminal methionine and with T821, A206V, S232T, Il22M; and A160T (underlined with semi—dotted/semi—solid line; SEQ ID NO: 30) and His—tag lined with dotted line; SEQ ID NO: 135).

SEQ ID NO: 139 Fusion protein of SMAP—29 (underlined with solid line; SEQ ID NO: 76), modified K2144 without N—terminal methionine and with C14S, C50S, Il22M; and A160T (underlined with semi—dotted/semi—solid line; SEQ ID NO: 31) and His—tag (underlined with dotted line; SEQ ID NO: 135).

SEQ ID NO: 140 Fusion protein of 9 (underlined with solid line; SEQ ID NO: 76), ed K2144 without N—terminal nine and with C14S, C23S and CSOS (underlined with semi— dotted/semi—solid line; SEQ ID NO: 32) and His—tag (underlined with dotted line; SEQ ID NO: 135).

SEQ ID NO: 141 Fusion protein of SMAP—29 (underlined with solid line; SEQ ID NO: 76), modified K2144 without N—terminal methionine and with T821, A206V, S232T, 1122M; A160T, C148 and C50S (underlined with semi—dotted/semi—solid line; SEQ ID NO: 33) and His-tag (underlined with dotted line; SEQ ID NO: 135).

SEQ ID NO: 142 Fusion protein of SMAP—29 (underlined with solid line; SEQ ID NO: 76), modified KZ144 without N—terminal nine and with T821, A206N, S232T, 1122M; A160T C148 and C50S (underlined with semi—dotted/semi—solid line; SEQ ID NO: 49) and g (underlined with dotted line; SEQ ID NO: 135).

SEQ ID NO: 151 Fusion n of SMAP-29 (underlined with solid line; SEQ ID NO: 76), K2144 without N—terminal nine (underlined with semi—dotted/semi—solid line; SEQ ID NO: 2) and His—tag (underlined with dotted line; SEQ ID NO: 135).

In a first aspect the present invention relates to a polypeptide comprising an amino acid sequence exhibiting at least about 90% sequence ty with the sequence of SEQ ID NO: 1, wherein SEQ ID NO: 1 is characterized by X1 may be absent or any amino acid, in ular M, X14 may be any amino acid, preferably S, R or N, more preferably S X23 may be any amino acid, preferably S, R or N, more preferably X50 may be any amino acid, preferably S, R or N, more preferably S X82 may be any amino acid, preferably T or I X122 may be any amino acid, preferably I or M X149 may be any amino acid, preferably M or P X154 may be any amino acid, preferably L or T X160 may be any amino acid, preferably A or T XI67 may be any amino acid, preferably I or L XI79 may be any amino acid, preferably N or F XI80 may be any amino acid, preferably M or E XI86 may be any amino acid, preferably V or Y X206 may be any amino acid, preferably A, N or V X212 may be any amino acid, preferably T or N X224 may be any amino acid, preferably P or Q X230 may be any amino acid, preferably N or Y X232 may be any amino acid, preferably S or T; and wherein the polypeptide does neither comprise the amino acid sequence of SEQ ID NO: 2, nor of SEQ ID NO: 3, nor of SEQ ID NO: 4.

In one embodiment, the t invention provides ptide comprising an amino acid sequence of SEQ ID NO: 1, wherein SEQ ID NO: 1 is characterized by X1 may be absent or any amino acid, X14 may be any amino acid, X23 may be any amino acid, X50 may be any amino acid, X82 may be any amino acid, X122 may be any amino acid, X149 may be any amino acid, X154 may be any amino acid, X160 may be any amino acid, X167 may be any amino acid, X179 may be any amino acid, X180 may be any amino acid, X186 may be any amino acid, X206 may be any amino acid, X212 may be any amino acid, X224 may be any amino acid, X230 may be any amino acid, X232 may be any amino acid; with the additional proviso that the sequence of SEQ ID NO: 1 exhibtis at least one of the following: i) X23 is S; ii) X14 and X50 are S; iii) X82 is I; iv) X122 is M and X160 is T; v) X206 is V; vi) X232 is T; wherein the polypeptide does neither comprise the amino acid sequence of SEQ ID NO: 2, nor SEQ ID NO:3 nor SEQ ID NO: 4.

The term "polypeptide" as used herein refers in particular to a polymer of amino acid es linked by peptide bonds in a specific ce. The amino acid es of a polypeptide may be modified by e.g. covalent attachments of various groups such as carbohydrates and phosphate. Other substances may be more loosely associated with the polypeptide, such as heme or lipid, giving rise to conjugated polypeptides which are also comprised by the term "polypeptide" as used herein. The term as used herein is intended to encompass also ns.

Thus, the term "polypeptide" also encompasses for example complexes of two or more amino acid polymer chains. The term "polypeptide " does encompass embodiments of polypeptides which exhibit optionally modifications typically used in the art, e.g. biotinylation, acetylation, pegylation, chemical changes of the amino-, SH- or carboxyl-groups (e.g. protecting groups) etc.. As will become apparent from the description below, the polypeptide according to the present invention may also be a fusion protein, i.e. linkage of at least two amino acid sequences which do not occur in this combination in nature. The term " ptide " as used herein is not limited to a specific length of the amino acid polymer chain, but typically the polypeptide will exhibit a length of more than about 50 amino acids, more than about 100 amino acids or even more than about 150 amino acids. Usually, but not necessarily, a typical polypeptide of the present invention will not exceed about 750 amino acids in length.

As used herein, the term "% sequence identity", has to be understood as follows: Two sequences to be ed are aligned to give a m correlation between the sequences. This may include inserting "gaps" in either one or both sequences, to e the degree of alignment. A % ty may then be determined over the whole length of each of the sequences being compared lled global alignment), that is particularly suitable for sequences of the same or similar length, or over shorter, defined lengths (so—called local alignment), that is more le for sequences of unequal length. In the above context, an amino acid sequence having a "sequence identity" of at least, for e, 95% to a query amino acid sequence, is intended to mean that the sequence of the subject amino acid sequence is identical to the query sequence except that the subject amino acid ce may include up to five amino acid alterations per each 100 amino acids of the query amino acid sequence. In other words, to obtain an amino acid sequence having a sequence of at least 95% identity to a query amino acid sequence, up to 5% (5 of 100) of the amino acid residues in the subject sequence may be inserted or substituted with another amino acid or deleted. Methods for comparing the identity and homology of two or more sequences are well known in the art.

The tage to which two sequences are identical can for example be determined by using a mathematical algorithm. A preferred, but not limiting, example of a mathematical algorithm which can be used is the algorithm of Karlin et a/. (1993), PNAS USA, 90:5873—5877. Such an algorithm is integrated in the BLAST family of programs, e.g. BLAST or NBLAST program (see also Altschul et al., 1990, J. Mol. Biol. 215, 403—410 or Altschul et al. (1 997), Nucleic Acids Res, 25:3389—3402), accessible through the home page of the NCBI at world wide web site ncbi.nlm.nih.gov) and FASTA (Pearson (1 990), Methods Enzymol. 83, 63—98; Pearson and Lipman (1988), Proc. Natl. Acad. Sci. U. S. A 85, 2444—2448.). Sequences which are identical to other ces to a certain extent can be identified by these programmes.

Furthermore, programs available in the Wisconsin Sequence Analysis Package, version 9.1 (Devereux et al, 1984, c Acids Res., 387-395), for example the programs BESTFIT and GAP, may be used to determine the % identity between two polypeptide sequences. T uses the "local homology" thm of (Smith and Waterman (1981 ), J. Mol. Biol. 147, 195— 197.) and finds the best single region of similarity between two sequences. If herein reference is made to an amino acid sequence sharing a particular extent of sequence identity to a reference sequence, then said difference in sequence is preferably due to conservative amino acid tutions. Preferably, such sequence s the activity of the reference sequence, e.g. albeit maybe at a slower rate. In on, if reference is made herein to a sequence sharing "at least" at n percentage of sequence identity, then 100% sequence ty are preferably not encompassed.

"Conservative amino acid substitutions", as used , may occur within a group of amino acids which have sufficiently similar physicochemical properties, so that a substitution between members of the group will preserve the biological activity of the molecule (see e.g.

Grantham, R. , Science 185, 862—864). Particularly, conservative amino acid substitutions are preferably substitutions in which the amino acids originate from the same class of amino acids (e.g. basic amino acids, acidic amino acids, polar amino acids, amino acids with aliphatic side chains, amino acids with positively or vely charged side chains, amino acids with aromatic groups in the side chains, amino acids the side chains of which can enter into hydrogen bridges, e.g. side chains which have a hydroxyl function, etc.).

Conservative substitutions are in the present case for example substituting a basic amino acid residue (Lys, Arg, His) for another basic amino acid residue (Lys, Arg, His), tuting an aliphatic amino acid residue (Gly, Ala, Val, Leu, lie) for another aliphatic amino acid residue, substituting an aromatic amino acid residue (Phe, Tyr, Trp) for another aromatic amino acid residue, substituting threonine by serine or leucine by cine. Further conservative amino acid ges will be known to the person skilled in the art.

The term ion" as used herein refers ably to the absence of 1, 2, 3, 4, 5 (or even more than 5) continuous amino acid residues in the derivative sequence in comparison to the respective reference sequence, either intrasequentially or at the N— or C—terminus.

The term "insertion" as used herein refers preferably to the additional intrasequential presence of 1, 2, 3, 4, 5 (or even more than 5) continuous amino acid residues in the derivative sequence in comparison to the respective reference sequence.

The term "addition" as used herein refers preferably to the additional presence of l, 2, 3, 4, 5 (or even more than 5) continuous amino acid residues at the N— and/or C—terminus of the derivative sequence in comparison to the respective reference sequence.

The term itution" as used herein refers to the presence of an amino acid residue at a certain on of the derivative sequence which is different from the amino acid residue which is present or absent at the corresponding position in the reference sequence. As mentioned above, preferably such substitutions are conservative substitutions.

The term ,,cell wall" as used herein refers to all components that form the outer cell enclosure of egative bacteria and thus guarantee their ity. In particular, the term ,,cell wall" as used herein refers to peptidoglycan, the outer ne of the Gram—negative bacteria with the lipopolysaccharide, the bacterial cell membrane, but also to additional layers deposited on the peptidoglycan as e.g. capsules, outer protein layers or slimes.

The term "amino acid sequence stretch" as used herein refers to a particular stretch of amino acid sequence in the amino acid ce of the polypeptide of the invention. Said ce refers to a sequence of a cationic e, a polycationic peptide, an amphiphatic e, a hobic peptide, a sushi peptide and/or an crobial peptide. The term does not refer to conventional tags like His—tags, such as HisS—tags, His6—tags, His7—tags, His8—tags, His9— tags, Hile—tags, Hisll—tags, Hile—tags, Hisl6—tags and His20—tags, Strep—tags, Avi—tags, Myc-tags, Gst—tags, JS—tags, cystein—tags, FLAG—tags or other tags known in the art, thioredoxin or maltose binding proteins (MBP). Preferably an amino acid sequence stretch as used herein as a length of about 6 to about 39 amino acid residues.

As used , the term nic peptide" refers preferably to a peptide having positively charged amino acid residues. Preferably a cationic peptide has a lue of 9.0 or greater.

Typically, at least four of the amino acid residues of the cationic peptide can be positively charged, for example, lysine or arginine. "Positively charged" refers to the side chains of the amino acid residues which have a net positive charge at about physiological conditions. The term "cationic peptide" as used herein refers also to polycationic peptides, but also includes cationic peptides which comprise for example less than 20%, preferably less than 10% positively charged amino acid residues.

The term "polycationic peptide" as used herein refers ably to a peptide composed of mostly positively charged amino acid residues, in particular lysine and/or arginine residues. A peptide is composed of mostly positively charged amino acid residues if at least about 20, 30, 40, 50, 60, 70, 75, 80, 85, 90, 95 or about 100 % of the amino acid residues are positively charged amino acid residues, in particular lysine and/or arginine residues. The amino acid residues being not positively charged amino acid residues can be neutrally d amino acid residues and/or vely charged amino acid residues and/or hydrophobic amino acid residues. Preferably the amino acid residues being not positively charged amino acid es are lly charged amino acid residues, in particular serine and/or glycine.

The term, "antimicrobial peptide" (AMP) as used herein refers preferably to any naturally occurring e that has microbicidal and/or microbistatic activity on for example bacteria, WO 71436 viruses, fungi, yeasts, mycoplasma and protozoa. Thus, the term "antimicrobial peptide" as used herein refers in particular to any e having anti—bacterial, anti—fungal, anti—mycotic, anti—parasitic, rotozoal, iral, anti—infectious, anti—infective and/or germicidal, algicidal, amoebicidal, microbicidal, bactericidal, fungicidal, parasiticidal, protozoacidal, protozoicidal properties. Preferred are anti—bacterial es. The antimicrobial peptide may be a member of the RNase A super family, a defensin, cathelicidin, granulysin, histatin, sin, dermicidine or hepcidin. The antimicrobial peptide may be naturally occurring in insects, fish, plants, arachnids, vertebrates or mammals. Preferably the antimicrobial peptide may be naturally occurring in insects, fish, plants, arachnids, vertebrates or mammals.

Preferably the antimicrobial peptide may be lly occurring in radish, silk moth, wolf spider, frog, preferably in Xenopus laevis, Rana frogs, more ably in Rana catesbeiana, toad, preferably Asian toad Bufo bufo gargarizans, fly, preferably in Drosophila, more preferably in Drosophila melanogaster, in Aedes aegypti, in honey bee, bumblebee, preferably in Bombus pascuorum, flesh fly, preferably in Sarcophaga peregrine, scorpion, horseshoe crab, catfish, preferably in Parasilurus asotus, cow, pig, sheep, e, bovine, monkey and human. As used herein, an icrobial peptide" (AMP) may in particular be a peptide which is not a ic peptide, polycationic peptide, amphiphatic peptide, sushi peptide, defensins, and hydrophobic peptide, but nevertheless exhibits antimicrobial activity.

The term "sushi peptide" as used herein refers to complement control proteins (CCP) having short consensus repeats. The sushi module of sushi peptides functions as a protein—protein interaction domain in many ent proteins. Peptides containing a Sushi domain have been shown to have antimicrobial activities. Preferably, sushi peptides are naturally occurring peptides.

The term "amphiphatic peptide" as used herein refers to synthetic peptides having both hilic and hydrophobic functional groups. Preferably, the term "amphiphatic peptide" as used herein refers to a peptide having a d ement of hydrophilic and hydrophobic groups e.g. amphiphatic peptides may be e.g. alpha helical, having predominantly non polar side chains along one side of the helix and polar residues along the rest of its surface.

The term "hydrophobic group" as used herein refers preferably to chemical groups such as amino acid side chains which are substantially water insoluble, but soluble in an oil phase, with the solubility in the oil phase being higher than that in water or in an aqueous phase. In water, amino acid es having a hydrophobic side chain interact with one another to generate a non—aqueous environment. Examples of amino acid residues with hydrophobic side chains are valine, cine, leucine, methionine, phenylalanine, tryptophan, cysteine, alanine, tyrosine, and proline residues The term "hydrophobic peptide" as used herein refers to a hydrophobic peptide, which is preferably composed of mostly amino acid residues with hydrophobic groups. Such peptide is preferably composed of mostly hydrophobic amino acid residues, i.e. at least about 20, 30, 40, 50, 60, 70, 75, 80, 85, 90, 95 or at least about 100 % of the amino acid residues are hydrophobic amino acid residues. The amino acid residues being not hydrophobic are preferably neutral and preferably not hydrophilic.

As used herein, the term "tag" refers to an amino acid sequence, which is typically in the art fused to or ed in another amino acid sequence for a) improving expression of the overall amino acid sequence or polypeptide, b) facilitating purification of the overall amino acid sequence or ptide, c) facilitating lisation of the overall amino acid sequence or polypeptide, and/or d) facilitating detection of the overall amino acid sequence or polypeptide. Examples for tags are His tags, such as His5—tags, His6—tags, His7—tags, HisS— tags, His9-tags, Hile—tags, Hisll—tags, Hile—tags, Hisl6—tags and His20—tags, Strep—tags, Avi-tags, Myc-tags, GST-tags, JS-tags, cystein-tags, FLAG-tags, HA-tags, thioredoxin or e binding ns (MBP), CAT, GFP, YFP, etc. The person skilled in the art will know a vast number of tags suitable for different technical applications. The tag may for e make such tagged polypeptide suitable for e.g. antibody binding in different ELISA assay formats or other technical applications.

The term ising" as used herein shall not be construed as being limited to the g "consisting of" (i.e. ing the presence of additional other matter). Rather, "comprising" implies that optionally additional matter may be present. The term "comprising" encompasses as particularly envisioned ments falling within its scope "consisting of" (i.e. excluding the presence of onal other matter) and "comprising but not consisting of" (i.e. requiring the presence of additional other matter), with the former being more preferred.

The polypeptide ing to the present invention may exhibit in the amino acid sequence ting at least about 90% sequence identity with the sequence of SEQ ID NO: 1 at least one (e.g. l, 2, 3, 4, 5, 6, 7, 8, 9, 10, ll, 12, 13, 14, 15, 16 or even all 17) of the following: X14 is not C; X23 is not C; X50 is not C; X82 is 1; X122 is M; X149 is P; X154 is T, X160 is T; X167 is L; X179 is F; X180 is E; X186 is Y; X206 is N or V, X212 is N; X224 is Q; X230 is Y and/or X232 is T. It is understood that the number indicating the position of the respective amino acid residue indicates the relative on in the sequence corresponding to SEQ ID NO: 1, and not to the overall amino acid sequence of the polypeptide according to the present invention, which may be longer.

The inventive polypeptide exhibits said at least 90% sequence identity. The inventive polypeptide may thus for example exhibit a higher level of sequence identity, 6.g. may exhibit at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 98,5%, at least about 99% (e.g. less than 3 amino acids deviation) at least about 99,3% , (e.g. less than 2 amino acids deviation), at least about 99,5%, at least about 99,6% or even 100% sequence identity with the sequence of SEQ ID NO: 1.

An inventive polypeptide comprising a sequence sharing a given level of sequence identity with the sequence of SEQ ID NO: 1 (or more specific sequences f, see below) can for example deviate from the reference sequence by addition, substitution, insertion or on of one or more amino acid es and all possible combinations thereof. Only for the sake of clarity it is pointed out that such ations refer to distinct positions in the sequence. A "deletion" followed by "addition", or "addition" followed by "deletion", of one or more amino acids, at the same relative position, is not an combination of an "addition" and "deletion" (or Vice versa) but falls under the term itution". Preferably, the ions in sequence from the sequence of SEQ ID NO: 1 (or more specific sequences thereof, see below) will be of conservative nature, e.g. conservative substitutions. Even more preferably the deviation in sequence is limited to those positions in SEQ ID NO: 1 (or more specific sequences thereof, see below), which have been identified to be non—critical for the tic activity, i.e. X1, X14, X23, X50, X82, X122, X149; X160, X167, X179, X180, X186; X206; X212; X224; X230 and/or X232.

Preferably, the polypeptide according to the present ion exhibits in the amino acid sequence ting at least about 90% sequence ty with the sequence of SEQ ID NO: 1 a ic acid residue at position 115. As shown in the publication Briers et al. (Molecular Microbiology (2007) 65(5), 1334—1344), the mutation E115A led to a loss in activity of about 70% of the enzyme. Thus, while an inventive polypeptide comprising said mutation will thus not be a loss of function polypeptide and may still serve various technical purposes, it is certainly preferred if such mutation is not present in the sequence stretch corresponding to SEQ ID NO: 1 within the inventive polypeptide.

In a particular preferred embodiment ing to the present invention the polypeptide of the present invention comprises the sequence of SEQ ID NO: I.

The inventors of the present invention have found out that three cysteine residues in the amino acid sequence of SEQ ID NO: 5 (K2144 endolysin sequence) are not essential for the enzymatic activity. Thus, in the sequence corresponding to SEQ ID NO: I nsus sequence of the present invention) of the inventive polypeptide (or g at least 90% sequence identity therewith), in some embodiments X14 is not C, X23 is not C, or X50 is not C. Combinations are possible, e.g. X14 and X23 are not C, X14 and X50 are not C, or X23 and X50 are not C. Likewise, it is also possible that r X14 nor X23 nor X50 are C. In principle said amino acid residues can be d or substituted by any other amino acid.

Examples for such other amino acids are S, R and N. Thus, X14 may for example be S, N, or R; more preferably S or R; most preferably R; X23 may for example be S, N, or R, more preferably S; and X50 may for e be S, N, or R, more preferably S or N; most preferably N. X14, X23 and X50 may of course exhibit different amino acid substitutions, for example X14 may be R while X23 and X50 are S; or X14 and X23 are S, while X50 is N; X14 may be R while X23 is S and X50 is N etc.. Any other ation conceivable is also contemplated by the present invention. Conservative amino acid substitutions are preferred.

Particularly preferred is a substitute of a serine residue for the cysteine e. Thus, in particularly preferred examples of the present invention X14 is S, X23 is S or X50 is S. Of course, it is also possible that X14 and X23 are S, or that X14 and X50 are S, or that X23 and X50 are S. X14, X23 and X50 may also all three be S. Absence of one or more or even of all of these cysteine e has the advantage that the risk of aggregation of the polypeptide according to the present invention, e.g. by red disulfide bridge ion, is reduced, and is thus an preferred embodiment of the present invention.

Aside of the dispensability of the above referenced cysteine residues, the inventors of the present invention have also elucidated that various other residues in the sequence of SEQ ID NO: 5 are also not essential and, moreover, may be replaced by other es, thereby WO 71436 sing for instance the temperature stability of the inventive polypeptide. Examples for such substitutions are X821, X122M, X149P; X154T, X160T, X167L, X179F, X180E, X186Y, X206V, X206N, X212N, X230Y and X232T. These substitutions may be present alone or in any combination. A typical combination is the ation of X122M and X160T.

Other examples of combinations are, without being limited o, X821, X206V plus X232T; X821, Xl22M, X160T, X206V, plus X232T; X821, X122M, X160T, X206N, plus X232T; X821, X122M, X206V, plus X232T; X821, X122M, X149P, X160T, X206V, plus X232T; X821, X122M, X160T, X180E, X206V, plus X232T; X821, X122M, X160T, X186Y, X206V, plus X232T; X821, X122M, X160T, X206V, X230Y, plus X232T; X821, X122M, X149P, X206V, plus X232T; X821, X122M, X149P, X160T, X206V, plus X232T; X821, X122M, X149P, X206V, plus X232T; X821, X122M, X149P, X167L, X206V, plus X232T; X821, X122M, X149P, X179F, X206V, plus X232T; X821, X122M, X149P, X206V, X212N plus X232T; X821, X122M, X149P, X206V, X224Q plus X232T; X821, X122M, X149P, X154T, X206V, plus X232T etc.. Of course, this second type of amino acid modifications may be combined with the above mentioned cysteine replacements in any type of combination conceivable. Examples of such combinations are, without being limited thereto, X148, X508, X122M and X160T; X148, X508, X821, X122M, X160T, X206V, and X232T; X148, X508, X821, X122M, X160T, X206N, and X232T; X148, X508, X821, X122M, X206V, and X232T; X148, X508, X821, X122M, X149P, X160T, X206V, and X232T; X148, X508, X821, X122M, X160T, X180E, X206V, and X232T; X148, X508, X821, X122M, X160T, X186Y, X206V, and X232T; X148, X508, X821, X122M, X160T, X206V, X230Y, and X232T; X14R, X508, X821, X122M, X160T, X206V, and X232T; X148, X50N, X821, X122M, Xl60T, X206V, and X232T; X14R, X508, X821, X122M, X149P, X206V, and X232T; X14R, X508, X821, X122M, X149P, X160T, X206V, and X232T; X14R, X50N, X821, X122M, X149P, X206V, and X232T; X14R, X50N, X821, X122M, X149P, X167L, X206V, and X232T; X14R, X50N, X821, X122M, X149P, X179F, X206V, and X232T; X14R, X50N, X821, X122M, X149P, X206V, X212N, and X232T; X14R, X50N, X821, X122M, X149P, X206V, X224Q and X232T; X14R, X50N, X821, X122M, X149P, X154T, X206V, and X232T; etc..

In SEQ ID NO: 1 (consensus ce of the present invention) the first amino acid residue is indicated as being either absent or any amino acid, in particular M. The results of the inventors, and of previous work (see of K2144 is dispensable. Thus, in some embodiments of the present invention the position of X1 in the sequence corresponding to SEQ ID NO: 1 in the inventive polypeptide is not M. If the polypeptide of the present invention exhibits for example N—terminally of the sequence ponding to SEQ ID NO: 1 further sequence elements, it may for instance for the purpose of effective expression in a host cell be useful, if the methionine at position 1 of SEQ ID NO: 1 is eliminated or replaced by another amino acid in order to avoid a ng codon in the corresponding nucleic acid sequence, potentially g to parallel expression of a polypeptide lacking the further sequence elements located more N—terminally. On the other hand, if there are no r N—terminal ce ts in the inventive polypeptide, X1 is of course preferably methionine (e.g. for expression purposes). For the enzymatic activity X1 is however never required.

Sequences falling under the definition of SEQ ID NO: 1, which have been ularly tested by the inventors, are for instance SEQ ID NOs: 6—27 (and corresponding ces without N—terminal methionine, SEQ ID NOs: 28—49).

It is understood that everything which has been set forth so far in terms of the generic sequence SEQ ID NO: 1 applies in similar manner also to more specific sequences. Thus, and only for the sake of clarity it is pointed out, that a polypeptide according to the present invention, comprising a sequence exhibiting at least 90% sequence identity with the generic sequence of SEQ ID NO: 1 as set out above, may in preferred embodiments certainly exhibit in analogous manner at least 90% sequence identity with more specific sequences of SEQ ID NO: 1 described or even particularly disclosed herein. Thus, in preferred ments of the present invention, the polypeptide of the present invention may for example comprise a sequence exhibiting at least 90% sequence identity with a sequence selected from any of SEQ ID NOs: 6—49, wherein the polypeptide does neither comprise the amino acid sequence of SEQ ID NO: 2, nor of SEQ ID NO: 3, nor of SEQ ID NO: 4.

The ptide according to the present invention may comprise aside of the enzymatic amino acid sequence, e.g. the ce ting at least about 90% sequence identity with the sequence of SEQ ID NO: 1 (or other sequences falling under these tion), further amino acid sequence stretches, e.g. as already disclosed in similar fashion in WO 49792. The polypeptide according to the present invention may for example comprise additionally at least one amino acid sequence stretch selected from the group ting of amphiphatic peptide, cationic peptide, polycationic peptide, hydrophobic peptide, or naturally occurring antimicrobial peptide, like sushi e and defensin. Such additional amino acid sequence stretches may improve the antibacterial properties of the inventive polypeptide. In some embodiments, the ive polypeptide may comprise at least two distinct amino acid sequence stretches selected from the group of amphiphatic peptide, cationic e, polycationic peptide, hydrophobic peptide, or naturally occurring antimicrobial peptide, like sushi peptide and defensin.

These one or more additional amino acid sequence stretches may be present N—terminally or C—terminally of the sequence exhibiting at least about 90% sequence ty with the sequence of SEQ ID NO: 1. They may for example be located at the N— or inus of the inventive polypeptide. Preferred es of such additional amino acid ce stretches (without being limited thereto), are the ce KRK and SEQ ID NOs: 50-120, as set out in more detail below. The polypeptide according to the present invention may comprise at least one onal amino acid sequence stretch selected from this group. For further guidance, in particular with respect to the generic and specific nature of possible additional amino acid sequence stretches, see for example also es for cationic and polycationic amino acid sequence stretches are listed in the following table.

Table 1: amino acid sequence stretch length SEQ.)ID NO: 91 A)m 91 U) 6‘ LI] 0 WA) U) W.N WA)WKQKKRK W RiRRRR KKKKKKKK KiKKRKK W5UWWRKKRKKRK W KiKKRKKi WWWKKKKKKKKKKKKK Wx0WWQKKRKKi KiKKRK W KiKKRKKx K itA15U50 {RRRRR{ RiRRRRR K RKKRKKRKKRKKRKK'RK K {KKRK {G SGKRKKRKKRK Kt{KKRKKRKRGSG SGKRKKRKKRK KfiKK Table 2: —sequence Bama- LL-37 LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES SEQ ID NO: 75 RGLRRLGRKIAHGVKKYGPTVLRIIRIAG Indolicidin ILPWKWPWWPWRR SEQ ID NO: 77 Cecropin P1 SWLSKTAKKLENSAKKRISEGIAIAIQGGPR SEQ ID NO: 79 Pleurocidin GWGSFFKKAAHVGKHVGKAALTHYL SEQ ID NO: 81 Cfggomflf‘ GGLKKLGKKLEGAGKRVFNAAEKALPVVAGAKALRK SEQ ID NO: 82 in A (D. GWLKKIGKKIERVGQHTRDATIQGLGIPQQAANVAATA SEQ ID NO. 83. gaster) RG Buforin || TRSSRAGLQFPVGRVHRLLRK SEQ ID NO: 84 SWLKKIGKKIERVGQHTRDATIQGLGIAQQAANVAATA SEQ ID NO: 85 Nigrocine 2 GLLSKVLGVGKKVLCGVSGLVC SEQ ID NO: 88 IWLTALKFLGKHAAKKLAKQQLSKL SEQ ID NO: 92 KGRGKQGGKVRAKAKTRSS SEQ ID NO: 93 AGRGKQGGKVRAKAKTRSSRAGLQFPVGRVHRLLRK Buforin I SEQ ID NO: 94 eptin 1 ALWKTMLKKLGTMALHAGKAALGAAADTISQGTQ SEQ ID NO: 95 Bactenecin 1 RLCRIVVIRVCR SEQ ID NO: 96 Thanatin GSKKPVPIIYCNRRTGKCQRM SEQ ID NO: 97 Brevinin 1T VNPIILGVLPKVCLITKKC SEQ ID NO: 98 SMLSVLKNLGKVGLGFVACKINIKQC SEQ ID NO: 99 Esculentin 1 SIIEEIELCGRKKIKNLLISGLKNVGKEVGMDVVRTGIKIAGC SEQ ID NO: 100 Tachyplesin RWCFRVCYRGICYRKCR SEQ ID NO: 101 Androctonin IKICRRRGGCYYKCTNRPY SEQ ID NO: 102 alpha-defensin PACIAGERRYGTCIYQGRLWAFCC SEQ ID NO: 103 beta-defensin NPVSCVRNKGICVPIRCPGSMKQIGTCVGRAVKCCRKK SEQ ID NO: 104 theta-defensin GFCRCLCRRGVCRCICTR SEQ ID NO: 105 defensin ATCDLLSGTGINHSACAAHCLLRGNRGGYCNGKAVCV SEQ ID NO. 106. saoecin A CRN Thionin (crambin) (TagquNSIVARSNFNVCRIPGTPEAICATYTGCIIIPGATCP SEQ ID NO: 107 defensin from QKLCQRPSGTWSGVCGNNNACKNQCIRLEKARHGSC SEQ 'D NO' 108_ NYVFPAHCICYFPC (EEEIEGPCAVWDNETCRRVCKEEGRSSGHCSPS SEQ ID NO: 109 DTHFPICIFCCGCCHRSKCGMCCKT SEQ ID NO: 110 SEEEPIRRPPIRPPFYPPFRPPIRPPIFPPIRPPFRPPLG SEQ ID NO: 111 PR_39 PYLPRPRPPPFFPPRLPPRIPPGFPPRFPPRF SEQ ID NO: 112 Pyrrhocoricin LPRPTPPRPIYNRN SEQ ID NO: 113 HiStatin 5 DSHAKRHHGYKRKFHEKHHSHRGY SEQ ID NO: 114 The at least one additional amino acid sequence stretch may be a sushi peptide which is described by Ding JL, Li P, Ho B Cell Mol Life Sci. 2008 Apr;65(7—8):1202—19. The Sushi peptides: ural characterization and mode of action against Gram—negative bacteria.

Especially preferred is the sushi 1 peptide ing to SEQ ID NO: 115. Other preferred sushi peptides are sushi peptides S1 and S3 and multiples thereof; FASEB J. 2000 (12):1801-13.

Preferred hydrophobic peptides are Walmaghl having the amino acid sequence according to SEQ ID NO: 116 and the hydrophobic peptide having the amino acid sequence Phe—Phe—Val— Ala-Pro (SEQ ID NO: 117).

Preferred amphiphatic peptides are a4—helix of T4 lysozyme according to SEQ ID NO: 118 and WLBU2—Variant having the amino acid ce according to SEQ ID NO: 119 and Walmagh 2 according to SEQ ID NO: 120.

As mentioned above, a polypeptide according to the present invention may comprise at least one additional amino acid sequence stretch selected from the group consisting of: KRK and SEQ ID NOs: 50—120. Corresponding examples are for instance polypeptides comprising a sequence selected from the group consisting of SEQ ID NOs: 7 (and ponding sequences without N—terminal methionine, SEQ ID NOs: 128—134.

A polypeptide according to the present invention comprises an amino acid sequence exhibiting at least about 90% sequence ty with the sequence of SEQ ID NO: 1, wherein the polypeptide does r se the amino acid sequence of SEQ ID NO: 2, nor of SEQ ID NO: 3, nor of SEQ ID NO: 4. Thus, a polypeptide of the present ion may also comprise an amino acid sequence ting at least 91,5 % sequence identity with an amino acid sequence selected from any of SEQ ID NOs: 121 — 134, wherein the polypeptide does neither comprise the amino acid sequence of SEQ ID NO: 2, nor of SEQ ID NO: 3, nor of SEQ ID NO: 4.

Such inventive polypeptide may thus for example comprise a sequence exhibiting a higher level of sequence identity than 91,5% with an amino acid sequence selected from any of SEQ ID NOs: 121 - 134, e.g. may exhibit at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 98,5%, at least about 98,75%, at least about 99% (e.g. less than 3 amino acids deviation) at least about 99,5% , (e.g. less than 2 amino acids deviation), at least about 99,6% or even 100% sequence identity with an amino acid sequence selected from any of SEQ ID NOs: 121 - 134.

In addition, and irrespective whether or not one or more additional amino acid ce stretches as set out above are present in the inventive polypeptide, the polypeptide may comprise onally one or more tag sequences. Such tag sequence may be t N— terminally or C—terminally of the sequence exhibiting at least about 90% sequence ty with the sequence of SEQ ID NO: 1. They may for example be located at the N— or C— terminus of the inventive polypeptide. In a preferred embodiment, the one or more tag sequence is located C—terminally of the amino acid sequence exhibiting at least 90% sequence identity with the sequence of SEQ ID NO: 1.

The one or more tag sequences may for example be linked to the amino acid sequence exhibiting at least 90% sequence identity with the sequence of SEQ ID NO: 1 directly or via a short linker of 1 to 10 amino acid residues, preferably 1 to 5 amino acid residues, even more preferably 1 to 2 amino acids. Linker sequences are preferably flexible sequences, comprising one or more glycine residues. Numerous examples for tags are known in the art, some of which have already been mentioned above. In the context of the present invention a particularly preferred tag sequence is a His—tag, preferably a His tag according to SEQ ID NO: The length of the ptide according to present invention is in principle not limited, but preferably the length will not be ively large. Preferably, a polypeptide according to the present invention has an overall length not exceeding about 320 amino acids, preferably not ing about 310 amino acids.

Specific examples of polypeptides according to the present invention can be selected from the group consisting of SEQ ID NOs: 136—142 (and corresponding ces without N—terminal methionine, SEQ ID NOS: 143-149).

A polypeptide ing to the present invention comprises an amino acid sequence exhibiting at least about 90% sequence identity with the ce of SEQ ID NO: 1, wherein the polypeptide does neither comprise the amino acid sequence of SEQ ID NO: 2, nor of SEQ ID NO: 3, nor of SEQ ID NO: 4. Thus, a polypeptide of the present invention may also comprise an amino acid sequence exhibiting at least 91,5 % sequence identity with an amino acid sequence selected from any of SEQ ID NOs: 136 — 149, wherein the ptide does neither comprise the amino acid sequence of SEQ ID NO: 2, nor of SEQ ID NO: 3, nor of SEQ ID NO: 4.

Such inventive polypeptide may thus for example comprise a sequence exhibiting a higher level of ce identity than 91,5% with an amino acid sequence selected from any of SEQ ID NOs: 136 — 149, e.g. may exhibit at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 98,5%, at least about 99%, at least about 99,25% (e.g. less than 3 amino acids deviation), at least about 99,5% (e.g. less than 2 amino acids deviation), at least about 99,6% or even 100% sequence identity with an amino acid ce selected from any of SEQ ID NOs: 136 — 149. Deviations from SEQ ID NOs: 136 - 149 may in ular occur in the two sequences linking the components SMAP29 peptide, modified K2144 endolysin and His—tag.

A polypeptide according to the present invention is preferably characterized by the ability to degrade the peptidoglycan of Gram—negative bacteria, in particular of Pseudomonas and/or Campylobacter bacteria. In particular, the polypeptide according to the present invention is preferably capable of degrading the peptidoglycan of Pseudomonas aeroginosa, in particular Pseudomonas aeroginosa PAOl, Campylobacterjejuni and/or Campylobacter coli.

The peptidoglycan degrading activity on gram negative bacteria can be measured by assays well known in the art, e.g. by muralytic assays in which the outer membrane of gram ve ia is permeabilized or removed (e.g. with chloroform) to allow the putative enzyme access to the peptidoglycan layer. If the enzyme is active, degradation of the oglycan layer will lead to a drop of turbidity, which can be measured photometrically (see for example Briers et al‘, J. Biochem. Biophys Methods 70: 531-533, (2007).

In a further aspect the present invention relates to a nucleic acid encoding a polypeptide according to the present invention. A person skilled in the art, having the racy of the genetic code in mind, will be aware of means to generate such nucleic acid.

In a further aspect, the present invention relates to a , such as an expression or cloning vector, which comprises a nucleic acid according to the present invention.

In a further , the present invention relates to a host cell comprising a ptide according to the present invention, a nucleic acid according to the present invention, and/or a vector according to the present invention.

In a further aspect, the present invention relates to composition comprising a polypeptide according to the present ion, a nucleic acid ing to the present invention, a vector according to the present invention, and/or a host cell ing to the present invention.

Preferably, said composition is a pharmaceutical composition comprising a pharmaceutical acceptable diluent, ent or carrier.

As set out above, a polypeptide according to the present invention ses an amino acid sequence exhibiting at least about 90% sequence identity with the sequence of SEQ ID NO: 1, wherein the polypeptide does r comprise the amino acid ce of SEQ ID NO: 2, nor of SEQ ID NO: 3, nor of SEQ ID NO: 4. However, in a further aspect, and slightly distinct from the above mentioned polypeptides of the invention, the t invention also relates additionally to a polypeptide comprising an amino acid sequence exhibiting at least about 90% sequence identity with the sequence of SEQ ID NO: 1, wherein the polypeptide does neither comprise the amino acid sequence of SEQ ID NO: 2, nor of SEQ ID NO: 152, nor of SEQ ID NO: 4. ally, said polypeptide of this additional aspect does also not comprise the amino acid sequence of SEQ ID NO: 3. All embodiments and combinations disclosed above, in the examples or in the claims for the polypeptide of the invention, and respective nucleic acids, vectors, host cells and itions, are specifically contemplated for this further aspect as well.

Examples In the following, ic examples illustrating various embodiments and aspects of the invention are presented. r, the present invention shall not to be limited in scope by the specific embodiments described herein. Indeed, various cations of the invention in addition to those described herein will become readily apparent to those d in the art from the foregoing description, accompanying figures and the examples below. All such modifications fall within the scope of the appended claims.

Example 1: Identification of mutations stabilizing K2144 endolysin For identification of advantageous sites of modification in endolysin K2144 (SEQ ID NO: 5), the inventors used in a first step targeted destabilization of the target protein. For this purpose an N—terminally truncated K2144 was generated (SEQ ID NO: 150) into which sequence mutations were introduced via random mutagenesis (error—prone PCR) ed by subsequent fusion and selection with a chloramphenicol assay (CAT .

The protein g temperature of promising candidates was determined by circular ism (CD). Changes of ellipticity for the ns were recorded at 220nm as a function of temperature using Jasco J-815 CD spectrometer and fitted to a simple sigmoid unfolding model using JASCO analysis software. The protein melting temperatures (Tmelt) were determined as midpoint of unfolding transition. The spectra were recorded at protein concentrations of 5.0—5.8uM with a heating rate of 1°C/min and incubation time of 35 in 410ul volume in a 1mm light path Hellma quartz cuvette. Measurements were performed in 50mM NaPh buffer, 300mM NaCl at pH of 7.4, 7.0, 6.2 and 5.7.

Some of the most promising ates identified are illustrated in the following table: WO 71436 Table 3 SOlublhty. . TM ATM Substitution* "_ + 53,5 0 54,1 + 0,6 55,8 + 2,3 T821— + 543 + 0,8 1122M + 565 + 3,0 A160T * Please note, the on indicated refers to the position in the sequence of K2144 sequence, SEQ ID NO: 5, and not to the position in SEQ ID NO: 150.

The thus identified stabilizing mutations can and were subsequently introduced into other sequences such as full length sequences, increasing stability there as well.

In a further step serine was used in some constructs for substitution of cysteine es C14, C23 and/or C50 (position indicated with respect to SEQ ID NO: 5; conservative substitutions). Other substituents at said positions tested were N and R.

In a further round of experiments, various combinations of mutations were tested in the context of the full length endolysin K2144 (SEQ ID NO: 5): Table 4 stitution mutatlons.

C148 C508 T8211122M A160T A206V SZ32T C148 C503 T8211122M A160T A206V N230Y 3232T C148 C503 T8211122M A160T M180E A206V 3232T C143 C503 T8211122M M149P A160T A206V 3232T ’ C143 C503 T8211122M A160T 567 +35 V186Y A206V 3232T C14R C503 T8211122M A160T A206V 3232T C148 C508 T8211122M T160A 58,3 +5,1 A206V SZ32T C14S C50N T82I1122M A160T A206V SZ32T C14R C503 T8211122M M149P A160T A206V 3232T C14R C503 T8211122M A206V 61 7 +85 3232T M149P ’ C14R C50N T8211122M M149P C14R C50N T8211122M M149P 8 63’4 "0’2 A206V 3232T C14R C50N T821 1122M M149P 8 62’8 "'9’6 A206V 3232T C14R C50N T8211122M M149P 61 5 +8 3 A206V 3232T ’ ’ WO 71436 C14R C50N T8211122M M149P 8 60,9 +7,7 A206V S232T * A TM vs. SEQ ID NO: 5 Example 2: Melting temperature of some polypeptides according to the present invention and MIC for selected bacterial strains For the construction of polypeptides according to SEQ ID NO 151 (w/o mutations) and SEQ ID NOs: 136 —l42 the lytic enzyme (gp144) of the Pseudomonas aeruginosa phage K2 was used. As peptide fusion r SMAP—29 was chosen. SMAP—29 was found in sheep leukocytes and consists of 29 amino acids (RGLRRLGRKIAHGVKKYGPTVLRIIRIAG; molecular weight: 3.3 kDa, SEQ ID NO: 76). It is built up of two LPS—binding sites which are connected by a central hinge.

Cloning The nucleic acid molecules encoding the respective peptide and endolysin were constructed with a NdeI (5’—CAT ATG—3’) restriction site at the 5’—end of the nucleic acid molecule and a XhoI C GAG—3’) restriction site at the 3’-end of the nucleic acid le. Peptide and endolysin are connected via a BamHI (5’—GGA TCC-3’).

Fusion proteins were ucted by linking at least two nucleic acid sequences using standard cloning techniques as bed e.g. by Sambrook et al. 2001, Molecular Cloning: A Laboratory Manual. Therefore the nucleic acid molecule encoding the peptide stretch was cleaved in a digest with the tive restriction enzymes NdeI and BamHI. Subsequently the d nucleic acids encoding the peptide stretch was ligated into the pET2l b expression vector (Novagen, Darmstadt, Germany), which was also cleaved in a digest with the respective restriction enzymes NdeI and BamHI before. Afterwards, the c acid molecule encoding the endolysin was cleaved in a digest with the ction enzyme BamHI and XhoI, so that the endolysin could be ligated into the pET2lb expression vector (Novagen, Darmstadt, Germany), which was also cleaved in a digest with the respective restriction enzymes BamHI and XhoI before.

The sequence of the peptide—endolysin fusions was controlled via DNA sequencing and correct clones were transformed into E.coli BL21(DE3)pLysS (Novagen, Darmstadt, Germany) for protein expression.

Purification Recombinant sion of the fusion proteins was done in E. coli BL21(DE3)pLysS cells (Novagen, Darmstadt, y). The cells were grown until an optical density of OD600nm = 0.5—0.8 was d. Then the expression of the fusion n was induced with 0.5 mM IPTG (isopropylthiogalactoside) and the expression was performed at 37°C for 4 h.

Cells were harvested by centrifugation for 20 min at 6000g and disrupted via sonication on ice. Soluble and insoluble fraction of the E. coli crude t were separated by centrifugation (Sorvall, $834, 30 min, 15 000 rpm). All proteins were purified by Ni2+ affinity chromatography (Akta FPLC, GE Healthcare) using the C—terminal His6 tag, encoded by the pET21b vector. Samples were iltrated (0.2 um) before every chromatographic step.

The Ni2+ affinity chromatography is performed in 4 subsequent steps, all at room temperature: 1. Equilibration of the p FF 5 m1 column (GE Healthcare) with up to 10 column volumes of Washing Buffer (20mM imidazole, lM NaCl and 20mM HEPES on pH 7.4) at a flow rate of 3—5 ml/min. 2. Loading of the total lysate with wanted target protein on the Histrap FF 5 ml column at a flow rate of 3-5 ml/min. 3. Washing of the column with up to 10 column volumes of Washing Buffer to remove d protein. 4. Elution of bounded target protein from the column with an increasing linear gradient of 15 column volumes of Elution Buffer (500mM imidazole, 500mM NaCl and 20mM HEPES on pH 7.4) to 100% at a flow rate of 3—5 ml/min.

The Hydrophobic Interaction Chromatography (HIC) is performed in 5 subsequent steps, all at I'l temperature: 1. Equilibration of the HiScreen Phenyl HP 5 ml column (GE Healthcare) with up to 5 column s of Washing Buffer (850mM ammonium sulfate, 500mM NaCl and 20mM HEPES on pH 7.4) at a flow rate of l—2ml/min 2. Preparation of the sample (5mg per lml column volume of the protein pool from Ni2+ affinity step) starts by first setting the protein concentration to 0.5mg/ml by adding a predefined amount of Washing Buffer from the Ni2+ Affinity step. Followed by adjusting the ammonium sulfate concentration by stepwise adding of a predefined amount of ammonium sulfate stock solution (3.8M) to a final concentration of approx. 850mM. 3. Loading of the prepared sample on the HiScreen Phenyl HP 5 ml column at a flowrate of 1—2ml/min. 4. g of the column with 5 column volumes of Washing Buffer to remove unbound protein.

. Elution of the target protein from the column with a step of 40% Elution Buffer (500mM NaCl and 20mM HEPES on pH 7.4) at a flow rate of 1—2 ml/min. The target n is eluted in broad peak at this step.

Buffer change by membrane dialysis: The elution pool of the HIC step is dialyzed (membrane: regenerated cellulose with MWCO: 6000—8000D) into storage buffer (500 mM NaCl and 20mM HEPES; pH7.4) at 4°C. Dialysis factor is 160 — 250.

Characterisation g temperatures characterizing stability of the ptides ing to SEQ ID NOs: 136 -l42 at elevated temperatures were determined by ar ism spectroscopy (CD) as mentioned above.

Activity of polypeptides according to SEQ ID NOs: 136 —142 on P. aeroginasa, C. jejuni and C. coli was characterised by ination of minimal inhibitory concentration (MIC) on the respective strains.

Determination of the Minimal Inhibitory Concentration (MIC) In analogy to the determination of the "Minimum inhibitory concentration (MIC)" for antibiotics, the MIC was determined as a microdilution test. The test on Campylobacter species is med completely at microaerophilic conditions and 42°C.

The setup of the experiment is the following: The respective overnight culture was diluted 1:10. PS. aeruginosa was incubated at 37°C up to OD600=0.6 (approx. 109 cells/ml). Campylobacter sp. were incubated microaerophilic up to OD600=0.08 x. 2,5x108 cells/ml). The bacterial culture was diluted to a concentration of 2x105 to 8x105 colony—forming—units per ml in Mueller—Hinton—broth (not cation—adjusted Mueller—Hinton—broth) and split in the required amount of tubes.

The polypeptide of interest was added in different concentrations (determined as ug/ml final concentration in the Mueller—Hinton—broth). In case of Ps. aeruginosa EDTA was added to a final concentration of 2 mM. In case of Campylobacter sp no EDTA was used.

The mixture was incubated overnight at 37°C for Ps. Aeruginosa and at 42°C for Campylobacter s. Bacterial growth was visibly determined by turbidity (in ison to negative control). The MIC was defined as the tration in the tube where no bacterial growth was observed. Positive (without ptide of interest and/or EDTA) and ve control (Mueller—Hinton—broth without ia) were included in the experiment.

The results are summarized in the following table: Table 5 MIC 0n MIC 0n MIC 0n PAOlp Camp. jejuni Camp. coli S82 S371 S344 [Mg/ml] [Hg/ml] [Hg/ml] SEQ Mutations* Concentration Tm 500 pM "0 EDTA "0 EDTA ID NO:- [by UV] 1°C] EDTA 151 5,5 11M 44,14 5 5 4 136 5,2 11M 49,07 5 5 4 138 55 HM 4757 4 139 56 MM 51,42 4 140 5,3 11M 50,31 5 3-4 2 141 5,9 pM 51,68 3-6 5-7 5 A206N SZ32T 142 1122M 5,3 11M 50,64 3 5-7 5 A160T g temperatures measured by CD, buffer: 50mM NaPh, pH 7.45 300mM NaCl Please note again, that the position indicated refers to the position in the sequence of K2144 sequence, SEQ ID NO: 5, and not to the position of the SEQ ID NO: indicated in the table.

The mutations introduced did thus not only increase melting ature of the polypeptides of SEQ ID NOs: 136 —142 vs the polypeptide of SEQ ID NO: 151, but did also not affect activity of the polypeptide, not even the sevenfold mutation of SEQ ID NO: 141.

Exam le 3: Tem erature stabilit of the 01 e tide in to SE ID NO: 139 and SE ID NO: 141 In order to illustrate that the sed melting temperature does indeed affect temperature stability of the respective d polypeptides, the inventors exposed exemplarily the mutated polypeptides of SEQ ID NO: 139 and SEQ ID NO: 141 to temperatures clearly exceeding the melting temperature of the native, non-mutated reference polypeptide (SEQ ID NO: 151).

For this purpose both polypeptides were ted to prolonged direct heating at temperatures of 51°C and 52°C. Subsequently, an activity test was performed on Pseudomonas nosa strain as a model system at adapted conditions.

The results are summarized in the following table: WO 71436 Table 6 MIC on PAOlp Concentration SEQ ID NO: Mutations Heating [pg/ml] [by UV] 500 "M EDTA 1min 51°C 2min 51°C 2min 52°C 1min 51°C 2min 51°C 2min 52°C Protein Buffer150mM NaPh, pH 7.45 300mM NaCl As previously, the position indicated refers to the position within the sequence portion corresponding to the K2144 sequence, SEQ ID NO: 5, and not to the position within the full- length sequence of the SEQ ID NO: indicated in the table.

Claims (30)

WHAT WE CLAIM IS:

1. Polypeptide comprising an amino acid ce of SEQ ID NO: 1, wherein SEQ ID NO: 1 is characterized by X1 may be absent or any amino acid, X14 may be any amino acid, X23 may be any amino acid, X50 may be any amino acid, X82 may be any amino acid, X122 may be any amino acid, X149 may be any amino acid, X154 may be any amino acid, X160 may be any amino acid, X167 may be any amino acid, X179 may be any amino acid, X180 may be any amino acid, X186 may be any amino acid, X206 may be any amino acid, X212 may be any amino acid, X224 may be any amino acid, X230 may be any amino acid, X232 may be any amino acid; with the additional proviso that the sequence of SEQ ID NO: 1 exhibtis at least one of the following: i) X23 is S; ii) X14 and X50 are S; iii) X82 is I; iv) X122 is M and X160 is T; v) X206 is V; vi) X232 is T; wherein the polypeptide does neither comprise the amino acid sequence of SEQ ID NO: 2, nor SEQ ID NO:3 nor SEQ ID NO: 4.

2. The polypeptide according to claim 1, wherein X14 is not C.

3. The polypeptide according to any one of the ing claims, wherein X23 is not C.

4. The polypeptide according to any one of the preceding claims, wherein X50 is not C.

5. The polypeptide according to any one of the preceding claims, n neither X14 nor X23 nor X50 are C.

6. The polypeptide ing to any one of the preceding claims, wherein X14 is S.

7. The polypeptide according to any one of the preceding claims, wherein X23 is S.

8. The ptide according to any one of the preceding claims, wherein X50 is S.

9. The polypeptide according to any one of the preceding claims, wherein X14 and X23 are S.

10. The polypeptide according to any one of the preceding claims, n X14 and X50 are S.

11. The ptide according to any one of the preceding claims, wherein X23 and X50 are S.

12. The polypeptide according to any one of the preceding claims, wherein X14, X23 and X50 are S.

13. The polypeptide according to any one of the preceding claims, wherein X82 is I.

14. The polypeptide according to any one of the preceding claims, wherein X122 is M.

15. The polypeptide according to any one of the preceding claims, wherein X160 is T.

16. The polypeptide according to any one of the preceding claims, wherein X206 is V.

17. The polypeptide according to any one of the ing claims, n X232 is T.

18. The polypeptide according to any one of the preceding , wherein X122 is M and X160 is T.

19. The polypeptide according to any one of the preceding claims, wherein X1 is not M.

20. The polypeptide according to any one of the preceding claims, n the polypeptide comprises a sequence selected from the group consisting of SEQ ID NOs: 6-49.

21. The polypeptide according to any one of the ing claims, wherein the polypeptide comprises additionally at least one amino acid sequence stretch selected from the group consisting of amphiphatic peptide, cationic peptide, polycationic peptide, hydrophobic peptide, naturally ing antimicrobial peptide, sushi peptide and defensin.

22. The polypeptide according to claim 21, wherein the polypeptide comprises at least one additional amino acid sequence stretch selected from the group consisting of: KRK and SEQ ID NOs: 50 - 120.

23. The ptide according to claim 21 or claim 22, wherein the polypeptide comprises at least one additional amino acid sequence stretch having the amino acid ce of SMAP-29, SEQ ID NO: 76.

24. The polypeptide according to claim 1, wherein the polypeptide comprises a sequence selected from from the group consisting of SEQ ID NOs: 121-134 or comprises a sequence selected from the group consisting of SEQ ID NOs: 136-149.

25. The polypeptide according to any one of the preceding claims, wherein the polypeptide degrades the peptidoglycan of Gram-negative bacteria, in particular of Pseudomonas and/or Campylobacter ia.

26. Nucleic acid encoding a polypeptide according to any one of claims 1 to 25.

27. Vector comprising a nucleic acid according to claim 26.

28. A non-human host cell comprising a polypeptide according to any one of claims 1 to 25, a c acid according to claim 26, and/or a vector according to claim 27.

29. Composition comprising a polypeptide according to any one of claims 1 to 25, a nucleic acid according to claim 26, a vector according to claim 27 and/or a host cell according to claim 28.

30. Composition according to claim 29, n the composition is a pharmaceutical composition comprising a pharmaceutical acceptable diluent, excipient or carrier. SE ID NO:1 XKVLRKGDRGDEVXQLQTLLNLXGYDVGKP DGI FGNNTFNQVVKFQKDNXLDSDG IVGK NTWAELFSKYSPP| PYKTI PMPXANKSRAAATPVMNAVENATGVRSQLLLTFASI ESAFDY EXKAKTSSATGWFQFLTGTWKTMIENYGXKYGVXTDPTGXLRKDPRXSALMGAELIKEX XNILRPXLKREPTDTDLYLAHFFGPGXARRFLXTGQNELAATHFXKEAQAXPXI FYNKDGS VYNLMDGKVAAHRK SE ID NO:2 KVLRKGDRGDEVCQLQTLLNLCGYDVGKPDG| FGNNTFNQVVKFQKDNCLDSDG IVGKN TWAELFSKYSPP| PYKTI PM PTANKSRAAATPVMNAVENATGVRSQLLLTFASI ESAFDYEI KAKTSSATGWFQFLTGTWKTMI ENYGMKYGVLTDPTGALRKDPRISALMGAELIKENMNI LRPVLKREPTDTDLYLAHFFGPGAARRFLTTGQNELAATHFPKEAQAN PSIFYNKDGSPK TIQEVYNLMDGKVAAHRK SEQ ID NO:3 1M=Selen0methi0nineg KVLRKGDRGDEVCQLQTLLNLCGYDVGKPDG| NQVVKFQKDNCLDSDG IVGKN TWAELFSKYSPP| PYKTI PM PTANKSRAAATPVMNAVENATGVRSQLLLTFASI ESAFDYEI KAKTSSATGWFQFLTGTWKTMI ENYGMKYGVLTDPTGALRKDPRISALMGAELIKENMNI LRPVLKREPTDTDLYLAHFFGPGAARRFLTTGQNELAATHFPKEAQAN PSIFYNKDGSPK TIQEVYNLMDGKVAAHRK SE ID N024 KVLRKGDRGDEVCQLQTLLNLCGYDVGKPDG| FGNNTFNQVVKFQKDNCLDSDG IVGKN TWAELFSKYSPP| PYKTI PM PTANKSRAAATPVMNAVENATGVRSQLLLTFASIASAFDYEI KAKTSSATGWFQFLTGTWKTMI ENYGMKYGVLTDPTGALRKDPRISALMGAELIKENMNI REPTDTDLYLAHFFGPGAARRFLTTGQNELAATHFPKEAQAN PSIFYNKDGSPK TIQEVYNLMDGKVAAHRK Fig.1a SE ID NO:5 MKVLRKGDRGDEVCQLQTLLNLCGYDVGKPDG| FGNNTFNQVVKFQKDNCLDSDG IVGK NTWAELFSKYSPP| PYKTI PMPTANKSRAAATPVMNAVENATGVRSQLLLTFASI ESAFDY El KAKTSSATGWFQFLTGTWKTM| ENYGMKYGVLTDPTGALRKDPRISALMGAELIKENM LKREPTDTDLYLAHFFGPGAARRFLTTGQNELAATHFPKEAQAN PSI FYNKDGSP KTIQEVYNLMDGKVAAHRK Fig.1b SEQ ID NO:136 MRGLRRLGRKIAHGVKKYGPTVLRI | RIAGGSKVLRKGDRGDEVSQLQTLLNLCGYDVGK SEQ ID NO:137 MRGLRRLGRKIAHGVKKYGPTVLRI | KVLRKGDRGDEVCQLQTLLNLCGYDVGK SE ID NO:138 MRGLRRLGRKIAHGVKKYGPTVLRI | RIAGGSKVLRKGDRGDEVCQLQTLLNLCGYDVGK SE ID NO:139 MRGLRRLGRKIAHGVKKYGPTVLRI | RIAGGSKVLRKGDRGDEVSQLQTLLNLCGYDVGK Fig.23 SE ID NO:14O LGRKIAHGVKKYGPTVLRI | RIAGGSKVLRKGDRGDEVSQLQTLLNLSGYDVGKP SE ID NO:141 MRGLRRLGRKIAHGVKKYGPTVLRI | RIAGGSKVLRKGDRGDEVSQLQTLLNLCGYDVGK SE ID NO:142 MRGLRRLGRKIAHGVKKYGPTVLRI | RIAGGSKVLRKGDRGDEVSQLQTLLNLCGYDVGK SE ID NO: 151 MRGLRRLGRKIAHGVKKYGPTVLRI | RIAGGSKVLRKGDRGDEVCQLQTLLNLCGYDVGK