Huang En, Yang Xu, Zhang Liwen, Moon Sun Hee, Yousef Ahmed E
Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Department of Food Science and Technology, The Ohio State University, 2015 Fyffe Road, Columbus, OH 43210, USA.
FEMS Microbiol Lett. 2017 Apr 1;364(8). doi: 10.1093/femsle/fnx049.
A new bacterial isolate, Paenibacillus sp. OSY-N, showed potent antimicrobial activity against Gram-negative and Gram-positive bacteria. Antimicrobials produced by this strain were purified by reverse-phase high-performance liquid chromatography. Structural analysis, using mass spectrometry, of a single active HPLC fraction revealed two known cyclic lipopeptides (BMY-28160 and permetin A), a new cyclic lipopeptide, and the linear counterparts of these cyclic compounds. The latter were designated as paenipeptins A, B and C, respectively. The paenipeptins have not been reported before as naturally occurring products. Paenipeptins B and C differ at the acyl side chain; paenipeptin C contains a C8-, instead of C7-fatty acyl side chain. To demonstrate unequivocally the antimicrobial activity of the linear forms of this family of cyclic lipopeptides, analogs of the paenipeptins were synthesized chemically and their antimicrobial activity was tested individually. The synthetic linear lipopeptide with an octanoic acid side chain (designated as paenipeptin C΄) showed potent antimicrobial activity with minimum inhibitory concentrations of 0.5-4.0 μg/mL for Gram-negative and 0.5-32 μg/mL for Gram-positive bacteria. Findings demonstrated that peptide cyclization in this lipopeptide family is not essential for their antimicrobial activity. Most importantly, linear lipopeptides are more accessible than their cyclic counterparts through chemical synthesis.
一种新的细菌分离株——芽孢杆菌属OSY-N，对革兰氏阴性菌和革兰氏阳性菌均表现出强大的抗菌活性。该菌株产生的抗菌物质通过反相高效液相色谱法进行纯化。利用质谱对单一活性高效液相色谱馏分进行结构分析，结果显示有两种已知的环脂肽（BMY-28160和permetin A）、一种新的环脂肽以及这些环状化合物的线性类似物。后者分别被命名为芽孢杆菌肽A、B和C。芽孢杆菌肽此前尚未作为天然产物被报道过。芽孢杆菌肽B和C在酰基侧链上有所不同；芽孢杆菌肽C含有一个C8 - 脂肪酰基侧链，而非C7 - 脂肪酰基侧链。为明确证明这一环脂肽家族线性形式的抗菌活性，化学合成了芽孢杆菌肽的类似物，并分别测试了它们的抗菌活性。带有辛酸侧链的合成线性脂肽（命名为芽孢杆菌肽C΄）表现出强大的抗菌活性，对革兰氏阴性菌的最低抑菌浓度为0.5 - 4.0 μg/mL，对革兰氏阳性菌的最低抑菌浓度为0.5 - 32 μg/mL。研究结果表明，该环脂肽家族中的肽环化对于其抗菌活性并非必不可少。最重要的是，通过化学合成，线性脂肽比其环状类似物更容易获得。
