PDF(Pubmed)
Abstract：
The physical and chemical properties of the outer membrane of Gram-negative bacteria including Escherichia coli have a significant impact on the antibacterial activity and uptake of antibiotics, including antimicrobial peptides and antisense peptide-peptide nucleic acid (PNA) conjugates. Using a defined subset of E. coli lipopolysaccharide (LPS) and envelope mutants, components of the LPS-core, which provide differential susceptibility toward a panel of bacterial penetrating peptide (BPP)-PNA conjugates, were identified. Deleting the outer core of the LPS and perturbing the inner core only sensitized the bacteria toward (KFF)3K-PNA conjugates, but not toward conjugates carrying arginine-based BPPs. Interestingly, the chemical composition of the outer LPS core as such, rather than overall hydrophobicity or surface charge, appears to determine the susceptibility to different BPP-PNA conjugates thereby clearly demonstrating the complexity and specificity of the interaction with the LPS/outer membrane. Notably, mutants with outer membrane changes conferring polymyxin resistance did not show resistance toward the BPP-PNA conjugates, thereby eliminating one possible route of resistance for these molecules. Finally, envelope weakening, through deletion of membrane proteins such as OmpA as well as some proteins previously identified as involved in cationic antimicrobial peptide uptake, did not significantly influence BPP-PNA conjugate activity.
摘要：
包括大肠杆菌在内的革兰氏阴性菌外膜的理化性质对抗菌活性和抗生素的摄取有显著影响,包括抗微生物肽和反义肽-肽核酸(PNA)缀合物。使用定义的大肠杆菌脂多糖（LPS）和包膜突变体的子集，LPS核心的组成部分，对一组细菌穿透肽（BPP）-PNA缀合物提供不同的易感性，已确定。删除LPS的外核并干扰内核仅使细菌对（KFF）3K-PNA缀合物敏感，但不是针对携带基于精氨酸的BPP的缀合物。有趣的是,外部LPS核心的化学成分，而不是整体疏水性或表面电荷，似乎确定了对不同BPP-PNA缀合物的敏感性,从而清楚地证明了与LPS/外膜相互作用的复杂性和特异性。值得注意的是,具有赋予多粘菌素抗性的外膜变化的突变体未显示出对BPP-PNA缀合物的抗性，从而消除了这些分子的一种可能的抗性途径。最后,包络弱化，通过删除膜蛋白，如OmpA以及一些先前鉴定为参与阳离子抗菌肽摄取的蛋白质，没有显着影响BPP-PNA缀合物的活性。
