Jenner Zachary B, Crittenden Christopher M, Gonzalez Martín, Brodbelt Jennifer S, Bruns Kerry A
Department of Chemistry and Biochemistry, Southwestern University, Georgetown, Texas, 78626.
Department of Microbiology, McGovern Medical School, formerly The University of Texas Health Science Center at Houston (UTHealth) Medical School, Texas, 77030.
Biopolymers. 2017 May;108(3). doi: 10.1002/bip.23006.
Antimicrobial peptides (AMPs) occur widely in nature and have been studied for their therapeutic potential. AMPs are of interest due to the large number of possible chemical structural combinations using natural and unnatural amino acids, with varying effects on their biological activities. Using physicochemical properties from known naturally occurring amphipathic cationic AMPs, several hydrocarbon-stapled lipopeptides (HSLPs) were designed, synthesized, and tested for antimicrobial properties. Peptides were chemically modified by N-terminal acylation, C-terminal amidation, and some were hydrocarbon stapled by intramolecular olefin metathesis. The effects of peptide length, amphipathic character, and stapling on antimicrobial activity were tested against Escherichia coli, three species of Gram-positive bacteria (Staphylococcus aureus, Bacillus megaterium, and Enterococcus faecalis), and two strains of Candida albicans. Peptides were shown to disrupt liposomes of different phospholipid composition, as measured by leakage of a fluorescent compound from vesicles. Peptides with (S)-2-(4'-pentenyl)-alanine substituted for l-alanine in a reference peptide showed a marked increase in antimicrobial activity, hemolysis, and membrane disruption. Stapled peptides exhibited slightly higher antimicrobial potency; those with greatest hydrophobic character showed the greatest hemolysis and liposome leakage, but lower antimicrobial activity. The results support a model of HSLPs as membrane-disruptive AMPs with potent antimicrobial activity and relatively low hemolytic potential at biologically active peptide concentrations.
抗菌肽（AMPs）广泛存在于自然界，并因其治疗潜力而受到研究。由于使用天然和非天然氨基酸存在大量可能的化学结构组合，且对其生物活性有不同影响，抗菌肽备受关注。利用已知天然存在的两亲性阳离子抗菌肽的物理化学性质，设计、合成了几种烃钉合脂肽（HSLP），并测试了它们的抗菌性能。通过N端酰化、C端酰胺化对肽进行化学修饰，部分肽通过分子内烯烃复分解进行烃钉合。针对大肠杆菌、三种革兰氏阳性菌（金黄色葡萄球菌、巨大芽孢杆菌和粪肠球菌）以及两株白色念珠菌，测试了肽长度、两亲性特征和钉合对抗菌活性的影响。通过荧光化合物从囊泡泄漏来测定，结果表明肽能破坏不同磷脂组成的脂质体。在参考肽中用（S）-2-（4'-戊烯基）-丙氨酸取代L-丙氨酸的肽，其抗菌活性、溶血作用和膜破坏作用显著增强。钉合肽表现出略高的抗菌效力；疏水性最强的肽溶血作用和脂质体泄漏最严重，但抗菌活性较低。结果支持了烃钉合脂肽作为具有强大抗菌活性且在生物活性肽浓度下溶血潜力相对较低的膜破坏抗菌肽的模型。
