Novel methods for displaying cyclic peptides on bacteriophage particles

Abstract

The present invention relates to methods for displaying cyclic peptides on the surface of bacteriophage particles and collections thereof.

1 . A nucleic acid sequence capable of displaying a cyclic peptide on the surface of a bacteriophage particle, wherein the nucleic acid encodes
 (a) a coat protein of said bacteriophage particle;   (b) a leader sequence which is recognized by a post-translationally modifying (PTM) enzyme, and   (c) a precursor cyclic peptide,   wherein the precursor cyclic peptide is located at the C-terminus of the coat protein of said bacteriophage particle,   and wherein said precursor cyclic peptide is able to form an intramolecular bond by coupling of one or more dehydrated residues to a cysteine or a lysine.   
     
     
         2 . The nucleic acid sequence of  claim 1  wherein said leader sequence is a leader sequence from a LanA precursor peptide or is a leader sequence derived from a LanA precursor peptide or is a leader sequence which bears a consensus motif from LanA precursor peptide 
     
     
         3 . A vector comprising the nucleic acid of  claim 1 . 
     
     
         4 . A vector comprising the nucleic acid of  claim 2 . 
     
     
         5 . A bacteriophage particle displaying a cyclic peptide on its surface obtainable by a method comprising:
 (a) providing a host cell harbouring a nucleic acid sequence encoding a precursor cyclic peptide;   (b) causing or allowing the expression of said precursor cyclic peptide;   (c) enzymatic dehydration of one or more amino acid residues within the precursor cyclic peptide;   (d) forming one or more intramolecular bonds by coupling of said one or more dehydrated residues to a cysteine or a lysine, thereby forming a cyclic peptide; and   (e) producing bacteriophage particles in said host cell, wherein said bacteriophage particles display said cyclic peptide on the surface and wherein said cyclic peptide is attached to the C-terminus of a coat protein of said bacteriophage particles.   
     
     
         6 . A diverse collection of bacteriophage particles of  claim 5 , wherein each of said bacteriophage particles display a cyclic peptide out of a diverse collection of cyclic peptides wherein said cyclic peptides comprise an intramolecular bond formed by coupling of one or more dehydrated residues to a cysteine or a lysine. 
     
     
         7 . A method for obtaining a cyclic peptide having a desired property, comprising:
 (a) providing the diverse collection of bacteriophage particles of  claim 6 ; and   (b) screening said diverse collection and/or selecting from said diverse collection to obtain at least one bacteriophage particle displaying a cyclic peptide having said desired property.