Membrane permeabilization, orientation, and antimicrobial mechanism of subtilosin A
Membrane permeabilization, orientation, and antimicrobial mechanism of subtilosin A
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DOI：
10.1016/j.chemphyslip.2005.06.003
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发表时间：
2005-10-01
影响因子：
3.4
通讯作者：
Ramamoorthy, A
中科院分区：
文献类型：
--
作者：
Thennarasu, S;Lee, DK;Ramamoorthy, A
枯草溶菌素 A 是一种由土壤细菌枯草芽孢杆菌产生的抗菌肽，对多种细菌（包括单核细胞增生李斯特菌）具有杀菌活性。最近的结构研究发现枯草溶菌素 A 以独特的方式进行翻译后修饰，使其成为一类新的细菌素。在本研究中，为了了解枯草溶菌素 A 膜破坏的机制，使用荧光、固态 NMR 和差示扫描量热法 (DSC) 实验对肽与模型磷脂双层的相互作用进行了表征。我们在这项研究中的结果表明，枯草溶菌素 A 以浓度依赖性方式与双层膜的脂质头基区域相互作用。荧光实验揭示了枯草溶菌素 A 与由 POPC、POPG 和大肠杆菌总脂质组成的小单层囊泡 (SUV) 的相互作用，并且该分子的至少一个边缘埋藏在膜双层中。在高浓度下，它会导致 POPC 和 POPE/POPG (7:3) 混合物从 SUV 中泄漏。 N-15 固态 NMR 数据表明环肽部分插入双层中，这与荧光数据一致。 P-31 和 H-2 NMR 实验和 DSC 数据支持枯草溶菌素 A 在脂质双层中采用部分埋藏方向的假设，表明它诱导脂质头基的构象变化和双层疏水区域的无序。这些结果表明，本研究中观察到的脂质扰动可能是枯草溶菌素 A 与脂质双层结合的后果之一，从而导致高肽浓度下的膜透化。 (c) 2005 Elsevier Ireland Ltd. 保留所有权利。
Subtilosin A is an antimicrobial peptide produced by the soil bacterium Bacillus subtilis that possesses bactericidal activity against a diverse range of bacteria, including Listeria monocytogenes. Recent structural studies have found that subtilosin A is posttranslationally modified in a unique way, placing it in a new class of bacteriocins. In this study, in order to understand the mechanism of membrane-disruption by subtilosin A, the interaction of the peptide with model phospholipid bilayers is characterized using fluorescence, solid-state NMR and differential scanning calorimetry (DSC) experiments. Our results in this study show that subtilosin A interacts with the lipid head group region of bilayer membranes in a concentration dependent manner. Fluorescence experiments reveal the interaction of subtilosin A with small unilamellar vesicles (SUVs) composed of POPC, POPG and E. coli total lipids, and that at least one edge of the molecule is buried in membrane bilayers. At high concentrations, it induces leakage from SUVs of POPC and POPE/POPG (7:3) mixture. N-15 solid-state NMR data suggests that the cyclic peptide is partially inserted into bilayers, which is in agreement with the fluorescence data. P-31 and H-2 NMR experiments and DSC data support the hypothesis that subtilosin A adopts a partially buried orientation in lipid bilayers, by showing that it induces a conformational change in the lipid headgroup and disordering in the hydrophobic region of bilayers. These results suggest that the lipid perturbation observed in this study may be one of the consequences of subtilosin A binding to lipid bilayers, which results in membrane permeabilization at high peptide concentrations. (c) 2005 Elsevier Ireland Ltd. All rights reserved.