Bacterial pilus protein complex FIMGT-DSF stabilized protein complexes for producing filamentous phages

A protein complex comprising

• a first polypeptide chain having the general formula (III) in N- to C-terminal direction
• X-SUB-DsF-Y (III),
• and
• a second polypeptide chain comprising at least one POI and having the general formula (IV) in N- to C-terminal direction
• X-FimGt(POI)-Y(POI)-CPF (IV),
• wherein
• X is absent or designates a bacterial leader sequence or translocation sequence,
• DsF designates a bacterial DsF-polypeptide comprising the N-terminal extension (donor strand) of bacterial type 1 pilus subunit FimF or a bacterial homolog thereof, wherein said DsF-polypeptide is capable of binding to FimGt,
• Y(POI) is absent or designates at least one of a branched linker sequence having POI attached thereto, a detectable peptide sequence and/or a peptide sequence for purifying said polypeptide chain,
• POI designates a protein of interest,
• FimGt(POI) designates a bacterial FimGt-polypeptide comprising a bacterial type 1 pilus subunit FimG polypeptide or a bacterial homolog thereof, wherein said FimGt-polypeptide is capable of binding to DsF, optionally having POI linked thereto,
• SUB designates a substrate, and
• CPF designates a coat protein of a filamentous phage.