Antibacterial activity of phosphono peptides based on 4-amino-4-phosphonobutyric acid.

Phosphono dipeptides based on 4-amino-4-phosphonobutyric acid (phosphonic acid analogue of glutamic acid, GluP) were synthesized and evaluated for their antibacterial activity. Dipeptides containing N-terminal alanine, leucine, isoleucine, phenylalanine or lysine showed marked antibacterial activity against Escherichia coli, whilst those containing alanine, leucine, valine or proline were active against Serratia marcescens. AlaGluP and LeuGluP were nearly equipotent with the respective dipeptides based on 1-aminoethylphosphonic acid (phosphonic acid analogue of alanine). The structure-activity relationship, i.e. dependence of the activity of phosphono dipeptides on the nature of their N-terminal component, indicated that transport of the peptide through the bacterial cytoplasmic membrane constitutes a crucial step in its antibacterial activity.