Medicinal Chemistry

Short Simple Linear Peptides Mimic Antimicrobial Complex Cyclodecapeptides Based on the Putative Pharmacophore

Abstract

Cuiping Guo, Long Pan, Shengwei Xiao, Heru Chen and Zhenyou Jiang

The sequence, -D-Tyr-Pro-Trp-D-Phe- has been identified from Loloatin C as a promising pharmacophore model for developing new antimicrobial peptides. Most of the linear peptides designed based on this sequence exhibits strong antimicrobial activities against Gram-positive bacteria S. aureus , S. albus and Gram-negative bacteria E. coli strains with MIC values ranging from 15.6 to 62.5 μg/mL, although they are inactive against fungus C. albicans , multi-drug resistant bacterial MRSA and K. pneumoniae . The linear hexapeptide, H-Asp-D-Tyr-Pro-Trp-D-Phe-Asn-OH (L1) is confirmed the most active peptide among them. L1 possesses s table α-helix domain conformation which is similar to Loloatin C in membrane mimetic solution. All the tested peptides demonstrate low hemolytic toxicity to rabbit red blood cells with EC 50 values higher than 120 μg/mL and low cytotoxicity to mouse fibroblast cells. The successful simplication of Loloatin C to a short linear peptide simplifies the synthetic process and lowers costs of production. The discussion of structure-activity relationship is also included