Prediction And Determination Of Bactericidal Activity Of A Group Of α-helical Antimicrobial Peptides

Objective:a-helical antimicrobial peptides is a group of broad spectrum agents against pathogens. A new chimeric antimicrobial peptide CP-P was synthesized with N terminus 1st to 11th amino acids (KWKSFIKKLTS) of CP26 and C terminus 10th to 18th amino acids (KFLHLAKKF) of P18. Their antibacterial and hemolytic activity in vitro were measured.Methods:A total of 19 peptides were obtained by solid phase peptide synthesis, the purity of CP-P and its derivatives checked by HPLC and their molecular weights by mass spectrometry. The minimum inhibitory concentration (MIC,μg/ml),minimal hemolytic concentration(MHC, μ.g/ml) and Therapeutic Index (MHC/MIC Ratio) of CP-P and its derivatives were determined and killing efficiency on Pseudomonas aeruginosa CMCC10104 and their hemolytic activity. We choose CP-P, K11S16 and 2 representative antimicrobial peptides as comparation to determine the kinetics of killing of both gram-positive and gram-negative bacteria. Then we chose K11S16 to further determination of its effectiveness of other clinical separation pathogen.Results and conclusion:The results showed killing efficiency of the modified peptides(S16, K11S 16) on Pseudomonas aeruginosa were more effective than that of P18. Especially K11S16’s MIC was 1.6μg/ml 1/4 of P18, meanwhile its MHC was greater than 500μg/ml and MHC/MIC Ratio was 8-fold of P18. We used rabbit burned model to evaluate K11S16’s antibacterial activity in vivo which indicates that it could be further developed as a candidate of choice.The frequent emergence of drug-resistant bacteria has created an urgent demand for new antimicrobial agents. Traditional methods of novel antibiotic development are almost obsolete. Antimicrobial peptides (AMPs) are now regarded as a potential solution to revive the traditional methods of antibiotic development, although, until now, many AMPs have failed in clinical trials. A comprehensive database of AMPs with information about their antimicrobial activity and cytotoxicity will help promote the process of finding novel AMPs with improved antimicrobial activity and reduced cytotoxicity and eventually accelerate the speed of translating the discovery of new AMPs into clinical or preclinical trials. LAMP, a database linking AMPs, serves as a tool to aid the discovery and design of AMPs as new antimicrobial agents. The current version of LAMP has 5,547 entries, comprising 3,904 natural AMPs and 1,643 synthetic peptides. The database can be queried using either simply keywords or combinatorial conditions searches. Equipped with the detailed antimicrobial activity and cytotoxicity data, the cross-linking and top similar AMPs functions implemented in LAMP will help enhance our current understanding of AMPs and this may speed up the development of new AMPs for medical applications. LAMP currently is freely available at:http://biotechlab.fudan.edu.cn/database/lamp.