The incorporation of a reduced amide bond, Ψ(CH2NH), into peptide results in an increase in the net positive charge and the perturbation of α-helical structure. By using this characteristic of the reduced amide bond, we designed and synthesized novel pseudopeptides containing reduced amide bonds, which had a great selectivity between bacterial and mammalian cells. A structureŐactivity relationship study on pseudopeptides indicated that the decrease in α-helicity and the increase in net positive charge in the backbone, caused by the incorporation of a reduced amide bond into the peptide, both contributed to an improvement in the selectivity between lipid membranes with various surface charges. However, activity results in vitro indicated that a perturbation of α-helical structure rather than an increase in net positive charge in the backbone is more important in the selectivity between bacterial and mammalian cells. The present result revealed that the backbone of membrane-active peptides were important not only in maintaining the secondary structure for the interactions with lipid membranes but also in direct interactions with lipid membranes. The present study showed the unique function of a reduced amide bond in cytolytic peptides and a direction for developing novel anti-bacterial agents from cytolytic peptides that act on the lipid membrane of micro-organisms.

This content is only available as a PDF.
You do not currently have access to this content.