The Contribution of the<i>N</i>-Terminal Structure of Polymyxin B Peptides to Antimicrobial and Lipopolysaccharide Binding Activity
作者:Naoki Sakura、Tatsuya Itoh、Yoshiki Uchida、Kazuhiro Ohki、Keiko Okimura、Kenzo Chiba、Yuki Sato、Hiroyuki Sawanishi
DOI:10.1246/bcsj.77.1915
日期:2004.10
To elucidate the N-terminal structure–activity relationships of polymyxin B peptides, seven polymyxin B component peptides, the structures of which having been elucidated, and seven N-terminal fatty acid and/or amino acid deletion analogs were synthesized, and their antimicrobial activities determined. The lipopolysaccharide (LPS) binding activities of synthetic peptides were evaluated using [Dab(Dansyl-Gly)1]-polymyxin B3 (Dab; l-α,γ-diaminobutyric acid) as a fluorescent probe. The results indicated that the fatty acyl moiety was not indispensable for LPS binding, but the C9 fatty acyl groups of polymyxin B peptides contributed to the binding affinity to a slightly greater extent than C8 or C7. The fatty acyl moieties of polymyxin B contributed greatly to the antimicrobial activity, while the distinct N-terminal structures of polymyxin B1–B6, bearing normal-, iso-, or anteiso-fatty acids, or 3-hydroxy-fatty acid with chain lengths between C7 and C9, did not affect bactericidal potency.
为了阐明多粘菌素 B 多肽 N 端结构与活性的关系,合成了 7 种已阐明其结构的多粘菌素 B 成分肽和 7 种 N 端脂肪酸和/或氨基酸缺失类似物,并测定了它们的抗菌活性。使用[Dab(Dansyl-Gly)1]-多粘菌素 B3(Dab;l-α,γ-二氨基丁酸)作为荧光探针,评估了合成肽的脂多糖(LPS)结合活性。结果表明,脂肪酰基对于 LPS 结合并非不可或缺,但多粘菌素 B 肽的 C9 脂肪酰基对结合亲和力的贡献略大于 C8 或 C7。多粘菌素 B 的脂肪酰基对抗菌活性有很大贡献,而多粘菌素 B1-B6 不同的 N 端结构(含有正常脂肪酸、异脂肪酸、反异脂肪酸或链长在 C7 和 C9 之间的 3-羟基脂肪酸)并不影响杀菌效力。