Li Dandan, Yang Yanhui, Li Ruifang, Huang Liang, Wang Zichao, Deng Qiwu, Dong Shuaibo
College of Biological Engineering, Henan University of Technology, Zhengzhou, China.
College of Information Science and Engineering, Henan University of Technology, Zhengzhou, China.
J Pept Sci. 2021 Sep;27(9):e3337. doi: 10.1002/psc.3337. Epub 2021 May 13.
Antimicrobial peptide L163 was computationally designed by our laboratory; L163 is active against multidrug-resistant (MDR) bacteria but is easily degraded in the plasma and by trypsin. Amino acid substitution, cyclization, and amino-terminal (N-terminal) acetylation were performed to obtain L163 analogs with high stability in the plasma and in trypsin solutions. The stability, antimicrobial activity, and biosafety of L163 and its analogs were investigated. Comparison with unmodified L163 indicated that N-terminal acetylation enhanced the stability against pH, plasma, and trypsin degradation, and phenylalanine (Phe) substitution for leucine (Leu) and cysteine bridge (S-S) cyclization decreased the stability. N-terminal acetylation also enhanced antimicrobial activity against MDR Streptococcus Sc181, Listeria monocytogenes, and Enterococcus E1478F; did not change the activity against MDR Staphylococcus aureus 9, Staphylococcus sciuri P254, and Staphylococcus aureus RN4220; and decreased the activity against Candida tropicalis, Candida albicans, and Enterococcus faecalis Fbc35. Phe substitution for Leu and S-S cyclization decreased the antimicrobial activity. The negative effect of these modifications was detected against biofilm formation by the tested microbial strains. Comparison of Phe substitution for Leu and S-S cyclization indicated that N-terminally acetylated L163 (L163-Ac) is the best candidate. L163-Ac peptide had the highest antibacterial activity and enhanced tolerance to temperature, pH, plasma, and trypsin and low toxicity.
抗菌肽L163是由我们实验室通过计算机设计的；L163对多重耐药（MDR）细菌具有活性，但在血浆中以及被胰蛋白酶作用时容易降解。进行了氨基酸取代、环化和氨基末端（N端）乙酰化以获得在血浆和胰蛋白酶溶液中具有高稳定性的L163类似物。研究了L163及其类似物的稳定性、抗菌活性和生物安全性。与未修饰的L163比较表明，N端乙酰化增强了对pH、血浆和胰蛋白酶降解的稳定性，苯丙氨酸（Phe）取代亮氨酸（Leu）以及半胱氨酸桥（S-S）环化降低了稳定性。N端乙酰化还增强了对多重耐药的链球菌Sc181、单核细胞增生李斯特菌和肠球菌E1478F的抗菌活性；对多重耐药的金黄色葡萄球菌9、松鼠葡萄球菌P254和金黄色葡萄球菌RN4220的活性没有改变；而对热带假丝酵母、白色念珠菌和粪肠球菌Fbc35的活性降低。Phe取代Leu以及S-S环化降低了抗菌活性。检测到这些修饰对受试微生物菌株形成生物膜有负面影响。Phe取代Leu和S-S环化的比较表明，N端乙酰化的L163（L163-Ac）是最佳候选物。L163-Ac肽具有最高的抗菌活性，并且对温度、pH、血浆和胰蛋白酶具有增强的耐受性以及低毒性。
