Self-made phage libraries with heterologous inserts in the Mtd of Bordetella bronchiseptica.

Phage display libraries are widely used as tools for identifying, dissecting and optimizing ligands. Development of a simple method to access greater library diversities could expedite and expand the technique. This paper reports progress toward harnessing the naturally occurring diversity generating retroelement used by Bordetella bronchiseptica bacteriophage to alter its tail-fiber protein. Mutagenesis and testing identified four sites amenable to the insertion of <19-residue heterologous peptides within the variable region. Such sites allow auto-generation of peptide libraries surrounded by a scaffold with additional variations. The resultant self-made phage libraries were used successfully for selections targeting anti-FLAG antibody, immobilized metal affinity chromatography microtiter plates and HIV-1 gp41. The reported experiments demonstrate the utility of the major tropism determinant protein of B.bronchiseptica as a natural scaffold for diverse, phage-constructed libraries with heterologous self-made phage libraries.