School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459, Singapore.
Biomacromolecules. 2010 Jan 11;11(1):60-7. doi: 10.1021/bm900896h.
Antimicrobial peptides (AMPs), particularly those effective against methicillin-resistant Staphylococcus aureus ( S. aureus ) and antibiotic-resistant Pseudomonas aeruginosa ( P. aeruginosa ), are important alternatives to antibiotics. Typical peptide synthesis methods involving solid-phase sequential synthesis are slow and costly, which are obstacles to their more widespread application. In this paper, we synthesize peptides via ring-opening polymerization of alpha-amino acid N-carboxyanhydrides (NCA) using a transition metal initiator. This method offers high potential for inexpensive synthesis of substantial quantities of AMPs. Lysine (K) was chosen as the hydrophilic amino acid and alanine (A), phenylalanine (F), and leucine (L) as the hydrophobic amino acids. We synthesized five series of AMPs (i.e., P(KA), P(KL), P(KF), P(KAL), and P(KFL)), varied the hydrophobic amino acid content from 0 to 100%, and determined minimal inhibitory concentrations (MICs) against clinically important Gram-negative and Gram-positive bacteria and fungi (i.e., Escherichia coli ( E. coli ), P. aeruginosa , Serratia marcescens ( S. marcescens ), and Candida albicans ( C. albicans ). We found that P(K(10)F(7.5)L(7.5)) and P(K(10)F(15)) show the broadest activity against all five pathogens and have the lowest MICs against these pathogens. For P(K(10)F(7.5)L(7.5)), the MICs against E. coli , P. aeruginosa , S. marcescens , S. aureus , and C. albicans are 31 microg/mL, 31 microg/mL, 250 microg/mL, 31 microg/mL, and 62.5 microg/mL, while for P(K(10)F(15)) the respective MICs are 31 microg/mL, 31 microg/mL, 250 microg/mL, 31 microg/mL, and 125 microg/mL. These are lower than the MICs of many naturally occurring AMPs. The membrane depolarization and SEM assays confirm that the mechanism of microbe killing by P(K(10)F(7.5)L(7.5)) copeptide includes membrane disruption, which is likely to inhibit rapid induction of AMP-resistance in pathogens.
抗菌肽（AMPs），特别是那些对耐甲氧西林金黄色葡萄球菌（金黄色葡萄球菌）和抗生素耐药铜绿假单胞菌（铜绿假单胞菌）有效的肽，是抗生素的重要替代品。涉及固相逐步合成的典型肽合成方法既缓慢又昂贵，这是它们更广泛应用的障碍。在本文中，我们使用过渡金属引发剂通过α-氨基酸 N-羧酸酐（NCA）的开环聚合合成肽。这种方法为廉价合成大量 AMP 提供了很大的潜力。赖氨酸（K）被选为亲水性氨基酸，丙氨酸（A）、苯丙氨酸（F）和亮氨酸（L）被选为疏水性氨基酸。我们合成了五组 AMPs（即 P(KA)、P(KL)、P(KF)、P(KAL)和 P(KFL)），改变了疏水性氨基酸的含量从 0 到 100%，并确定了最小抑菌浓度（MIC）对临床重要的革兰氏阴性和革兰氏阳性细菌和真菌（即大肠杆菌（大肠杆菌）、铜绿假单胞菌（铜绿假单胞菌）、粘质沙雷氏菌（粘质沙雷氏菌）和白色念珠菌（白色念珠菌））。我们发现 P(K(10)F(7.5)L(7.5)) 和 P(K(10)F(15)) 对所有五种病原体表现出最广泛的活性，并且对这些病原体的 MIC 最低。对于 P(K(10)F(7.5)L(7.5))，对大肠杆菌、铜绿假单胞菌、粘质沙雷氏菌、金黄色葡萄球菌和白色念珠菌的 MIC 分别为 31μg/mL、31μg/mL、250μg/mL、31μg/mL 和 62.5μg/mL，而对于 P(K(10)F(15))，相应的 MIC 分别为 31μg/mL、31μg/mL、250μg/mL、31μg/mL 和 125μg/mL。这些都低于许多天然 AMP 的 MIC。膜去极化和 SEM 测定证实，P(K(10)F(7.5)L(7.5)) copeptide 杀死微生物的机制包括膜破坏，这可能抑制病原体中 AMP 耐药的快速诱导。
