Interaction of colicin E7 with the major coat protein (g8p) may confer limited protection on colicinogenic Escherichia coli against M13 bacteriophage infection

摘要

Colicin release provides producer strains with a competitive advantage under certain circumstances. We found that propagation of M13 bacteriophage in cells producing colicin E7 is impaired, without alteration in the efficiency of bacteriophage adsorption, as compared with non-producing cells. In contrast to the protective effect of the colicin against M13 bacteriophage infection, the endogenously expressed colicin does not confer limited protection against transfection with M13 bacteriophage DNA. Furthermore, it was found that the translocation-receptor-binding domain and toxicity domain of the colicin are able to interact with the M13 major coat protein, g8p, during bacteriophage infection. Based on these observations, we propose that interaction between colicin E7 and g8p during infection interferes with g8p depolymerizing into the cytoplasmic membrane during bacteriophage DNA penetration, thus resulting in the limited protection against M13 bacteriophage infection.