Distinct bactericidal activities of bovine lactoferrin peptides LFampin 268–284 and LFampin 265–284: Asp-Leu-Ile makes a difference.

摘要

Two lactoferrampin (LFampin) peptides derived from bovine lactoferrin were compared with respect to their bactericidal activities. LFampin 265–284 killed a set of Gram-positive bacteria that were resistant to LFampin 268–284. The presence of 265Asp-Leu-267Ile did not simply lead to an overall increased potency, since higher concentrations of LFampin 265–284 than LFampin 268–284 were needed to kill the Gram-negative bacteria that were tested. The Asp-Leu-Ile sequence enhances the propensity of LFampin to adopt an α-helix, as shown by circular dichroism spectroscopy. These results suggest that the helical conformation of the peptide is an important determinant of the susceptibility of Gram-positive bacteria.