Colicin N interaction with sensitive Escherichia coli cells: in situ and kinetic approaches

The kinetics of colicin N binding to the Escherichia coli surface, comprising the recognition of and association with cell-surface-exposed sites of OmpF porin, is a rapid event taking place during the first seconds of incubation. Immunogold labelling demonstrates the membrane localization of the colicin N bound to sensitive cells. Analyses of colicin-induced efflux indicate a short lag before the onset of cytoplasmic K+ release. This delay reflects the time necessary for translocation from the external side and pore-forming insertion into the cytoplasmic membrane.