Probing voltage dependence interaction of cationic peptides with bacterial porins at a single-molecule level

Abstract

This study investigates the interaction between the cationic antimicrobial peptide protamine and bacterial porin OmpF (E. coli) at the single-molecule level. Using high-resolution conductance measurements in planar lipid bilayers, strong voltage- and concentration-dependent ion current blockages with OmpF, indicating significant protamine binding were observed. Further analysis revealed that peptide length influences binding kinetics, with longer peptides showing reduced affinity and slower exchange rates. These findings demonstrate that OmpF is a tractable model for studying cationic peptide-channel interactions and translocation mechanisms relevant to antimicrobial action.