Structure-activity relationships of a snake cathelicidin-related peptide, BF-15.
Cathelicidin-BF15 (BF-15) is a 15-mer peptide derived from Cathelicidin-BF (BF-30), which is found in the venom of the snake Bungarus fasciatus and exhibits broad antimicrobial activity. Since BF-15 retains most part of the antimicrobial activity of BF-30 but has significantly reduced haemolytic activity and a much shorter sequence length (and less cost), it is a particularly attractive template around which to design novel antimicrobial peptides. However, the structure-activity relationship of it is still unknown. We designed and synthesized a series of C-terminal amidated analogs of BF-15 based on its amphipathic α-helix structure. And we characterized their antimicrobial potency and haemolytic activity. We identified the amidated BF-15 (analog B1) with potent antimicrobial activity against several antibiotic-resistant bacteria (MICs between 1 and 64 μg/mL, 2-16-folds higher than BF-30) and much lower haemolytic activity. The subsequent circular dichroism study results showed a typical α-helix pattern of analog B1 and the content of the α-helix structure of it increased significantly comparing with BF-30, which indicates the peptide sequence of BF-15 may provide a major contribution to the α-helix content of the whole BF-30 sequence. The peptide induced chaotic membrane morphology and cell debris as determined by electron microscopy. This suggests that the antimicrobial activity of B1 is based on cytoplasmic membrane permeability. Taken together, our results suggested that peptide B1 should be considered as an excellent candidate for developing therapeutic drugs.
Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, PR China.
Wei
W
Chen
Baowei
B
Yang
Huimin
H
Zhou
Lidan
L
Sun
Jie
J
Dou
Hai
H
Qian
Wenlong
W
Huang
Yicheng
Y
Mei
Jing
J
Han
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D017838:Bungarus; D002176:Candida albicans / Q000187:drug effects; D054804:Cathelicidins / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D002942:Circular Dichroism; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects; D053878:Hemolytic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000648:ultrastructure; D060327:Solid-Phase Synthesis Techniques / Q000379:methods; D013211:Staphylococcus aureus / Q000187:drug effects / Q000648:ultrastructure; D013329:Structure-Activity Relationship
D000900:Anti-Bacterial Agents; D054804:Cathelicidins; D053878:Hemolytic Agents