Interaction of the Staphylococcin-like Peptide Pep 5 with Cell Walls and Isolated Cell Wall Components of Gram-Positive Bacteria

Abstract

Unlike bacteriocins of Gram-negative bacteria, the strongly basic staphylococcin-like peptide Pep 5 lacked specific receptor mediated binding to sensitive Gram-positive bacteria. Studies with whole cells, purified cell walls, teichoic acids, and lipoteichoic acids strongly suggested that it binds reversibly via electrostatic interaction to negatively charged groups. Thus, Pep 5 binding could be reversed by sufficiently high concentrations of monovalent (K +, 150–250 mM) and divalent (Ca 2+, 15–30 mM) cations (Fig. 1, 2) and by low pH (pH 2), where Pep 5 binding groups are protonated. Cells of Staphylococcus cohnii 22 with a reduced teichoic acid content showed a reduced Pep 5 binding capacity (Fig. 3). The results indicate that teichoic, teichuronic, and lipoteichoic acids are the unspecific cell wall binding sites for Pep 5.