Abstract: Disclosed is a polypeptide comprising at least two microproteins, which preferably comprise an amino acid sequence having a specific binding activity to a target protein. Furthermore, disclosed are polynucleotides encoding such a polypeptide as well as pharmaceutical compositions and kits comprising said polypeptide or polynucleotide. Also disclosed herein are methods of treatments and second medical uses applying the disclosed polypeptide or polynucleotide. Additionally, the disclosure of the present application relates to a method for forming a covalent bond in a microprotein which can be used for producing the disclosed polypeptides.

Abstract: The inventive method allows peptides or polypeptides to be exposed on the surface of gram-negative host bacteria using specific intimin-based anchor modules. Intimins with shortened carboxy terminals have been found to be particularly suitable anchor modules for passenger domains in the exterior E. coli cell membrane. According to the method, host bacteria are transformed using vectors, on which are located a fused nucleic acid sequence consisting of a sequence segment which codes for an intimin with a shortened carboxy terminal and a nucleic acid sequence segment which codes for the passenger peptide that is to be exposed. The invention permits a particularly large number of passenger domains to be exposed on the cell surface of the bacteria, without adversely affecting the viability of the bacteria.