Detection of molecular interactions by using a new peptide-displaying bacteriophage biosensor

Foreign peptides fused to the carboxy terminus of P22 tailspike protein are solvent-exposed and highly antigenic when displayed on the surface of infectious virus particles. Binding of an anti-peptide specific Fab antibody fragment enhances the infectivity of chimeric bacteriophage particles in a titre-dependent fashion. Although the precise molecular basis of this enhanced infectivity remains unclear, experimental data and modelling approaches suggest that the antibody binding might restore conformational impairments in the assembled tail protein affecting its activity and performance during infection. These results suggest that in addition to free enzymes, peptide-displaying bacteriophages could be engineered as new biosensors to detect molecular interactions by using natural viral enzymes critical for cell infection.