Antimicrobial properties and interaction of two Trp-substituted cationic antimicrobial peptides with a lipid bilayer
Antimicrobial properties and interaction of two Trp-substituted cationic antimicrobial peptides with a lipid bilayer
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两种色氨酸取代的阳离子抗菌肽与脂质双层的抗菌特性和相互作用
DOI：
10.1038/ja.2014.4
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发表时间：
2014-05-01
影响因子：
3.3
通讯作者：
Shang, Dejing
中科院分区：
文献类型：
--
作者：
Bi, Xiaonan;Wang, Che;Shang, Dejing
色氨酸（Trp）残基具有很强的膜破坏活性，这一特性赋予了含Trp的抗菌肽（AMP）与细菌细胞膜表面相互作用的独特能力，从而可能改善抗菌性能。在这项研究中，我们调查的影响色氨酸残基工程有一个独特的偏好的界面区域的脂质双层的抗菌活性。通过在L-K6肽的不同位置用两个Trp残基取代Ile或Leu，设计了两个Trp取代的AMP（I1 WL 5 W和I4 WL 5 W），并测定了它们的抗菌活性和膜作用机制。与L-K6相比，I1 WL 5 W和I4 WL 5 W对革兰氏阴性菌和革兰氏阳性菌均表现出显著更高的抗菌活性和更低的细胞毒性。色氨酸取代肽在水溶液中呈无序结构，在50%三氟乙醇/水和30 m M SDS溶液中呈α-螺旋结构。I1 WL 5 W和I4 WL 5 W导致钙黄绿素从含有膜的脂质体中显著渗漏，所述膜模拟大肠杆菌和金黄色葡萄球菌的膜。扫描电镜分析表明，I1 WL 5 W和I4 WL 5 W通过破坏细菌细胞膜而杀死细菌。此外，从各种脂质体，模拟不同的细胞膜的荧光和淬灭数据表明，色氨酸取代的肽可以插入到脂质双层和诱导的色氨酸残基的发射光谱的蓝移。I1 WL 5 W和I4 WL 5 W对丙烯酰胺或KI淬灭剂也不太敏感。目前的工作可能是重要的设计新的色氨酸含有肽表现出强大的抗菌能力，通过穿透细菌膜。
Tryptophan (Trp) residues reportedly exhibit a strong membrane-disruptive activity, and this property endows Trp-containing antimicrobial peptides (AMPs) with a unique ability to interact with the surface of bacterial cell membranes, possibly improving antimicrobial properties. In this study, we investigated the influence of Trp residues engineered to have a distinct preference for the interface region of lipid bilayers on antimicrobial activity. We designed two Trp-substituted AMPs (I1WL5W and I4WL5W) by replacing Ile or Leu residues with two Trp residues at different positions in the L-K6 peptide, and determined their antimicrobial activity and mechanism of membrane action. Both I1WL5W and I4WL5W exhibited significantly higher antimicrobial activity and lower cytotoxicity against Gram-negative and Gram-positive bacteria compared with L-K6. The Trp-substituted peptides had a disordered structure in aqueous solution and adopted an α-helical structure in solutions of 50% trifluoroethanol/water and 30 m M SDS. I1WL5W and I4WL5W caused a significant leakage of calcein from liposomes containing membranes that mimicked those of Escherichia coli and Staphylococcus aureus. Scanning electron microscopy analysis suggested that I1WL5W and I4WL5W killed bacteria by disrupting bacterial cell membranes. Furthermore, fluorescence and quenching data from a variety of liposomes, which mimic different cell membranes, indicated that the Trp-substituted peptides could insert into the lipid bilayers and induce blue shifts in the emission spectra of the Trp residues. I1WL5W and I4WL5W were also less susceptible to acrylamide or KI quenchers. The current work may be important for designing novel Trp-containing peptides exhibiting strong antimicrobial abilities by penetrating bacterial membranes.