Program in Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
Program in Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
J Biol Chem. 2023 Nov;299(11):105266. doi: 10.1016/j.jbc.2023.105266. Epub 2023 Sep 19.
With antimicrobial resistance (AMR) remaining a persistent and growing threat to human health worldwide, membrane-active peptides are gaining traction as an alternative strategy to overcome the issue. Membrane-embedded multi-drug resistant (MDR) efflux pumps are a prime target for membrane-active peptides, as they are a well-established contributor to clinically relevant AMR infections. Here, we describe a series of transmembrane peptides (TMs) to target the oligomerization motif of the AcrB component of the AcrAB-TolC MDR efflux pump from Escherichia coli. These peptides contain an N-terminal acetyl-A-(Sar) (sarcosine; N-methylglycine) tag and a C-terminal lysine tag-a design strategy our lab has utilized to improve the solubility and specificity of targeting for TMs previously. While these peptides have proven useful in preventing AcrB-mediated substrate efflux, the mechanisms by which these peptides associate with and penetrate the bacterial membrane remained unknown. In this study, we have shown peptide hydrophobic moment (μH)-the measure of concentrated hydrophobicity on one face of a lipopathic α-helix-drives bacterial membrane permeabilization and depolarization, likely through lateral-phase separation of negatively-charged POPG lipids and the disruption of lipid packing. Our results show peptide μH is an important consideration when designing membrane-active peptides and may be the determining factor in whether a TM will function in a permeabilizing or non-permeabilizing manner when embedded in the bacterial membrane.
由于抗菌药物耐药性（AMR）仍然是全球范围内对人类健康的持续且日益严重的威胁，因此膜活性肽作为克服这一问题的替代策略受到了关注。膜嵌入的多药耐药（MDR）外排泵是膜活性肽的主要靶标，因为它们是导致临床上相关的 AMR 感染的一个既定因素。在这里，我们描述了一系列跨膜肽（TM），以针对大肠杆菌的 AcrAB-TolC MDR 外排泵的 AcrB 成分的寡聚基序。这些肽包含 N 端乙酰基-A-（Sar）（肌氨酸；N-甲基甘氨酸）标签和 C 端赖氨酸标签-这是我们实验室用来提高 TM 的溶解性和靶向特异性的设计策略。虽然这些肽已被证明在防止 AcrB 介导的底物外排方面非常有用，但这些肽与细菌膜结合和穿透的机制仍不清楚。在这项研究中，我们已经表明，肽的疏水性矩（μH）-测量脂溶性α-螺旋一侧的疏水性集中程度-驱动细菌膜的通透性和去极化，可能通过带负电荷的 POPG 脂质的横向相分离和脂质堆积的破坏来实现。我们的结果表明，当设计膜活性肽时，肽的μH 是一个重要的考虑因素，并且当嵌入细菌膜时，肽μH 可能是 TM 是否以通透或不通透的方式发挥作用的决定因素。
