Antibacterial peptide with strong anti-Gram-negative bacteria activity. Significantly contributes to antibacterial activity against Enterobacter cloacae but not Providencia burhodogranariea. Inhibitor of bacterial translation machinery that targets translation termination in a prfA- or prfB-dependent manner. Binds within the nascent peptide exit tunnel of the bacterial large ribosomal subunit, potentially interfering with nascent chain translocation that occurs post-peptide bond formation. Binds prfA/RF1 (and potentially prfB/RF2), trapping it on the ribosome after release of the nascent polypeptide chain and preventing further translation. The resulting depletion of peptide chain release factors further disrupts bacterial translation by preventing ribosomal peptide chain release and inducing stop codon readthrough. Entry into target Escherichia coli cells requires the bacterial peptide antibiotic transporter sbmA