Department of Respiratory Medicine, Beijing Hospital, Beijing 100730, China.
School of Life Science, Liaoning Normal University, Dalian 116081, China.
J Photochem Photobiol B. 2019 Nov;200:111645. doi: 10.1016/j.jphotobiol.2019.111645. Epub 2019 Oct 13.
Antimicrobial peptide W3R6 was derived from chensinin-1b and showed potential as a novel antibiotics. However, W3R6 was susceptible to protease cleavage, which limited its therapeutic application. To improve the proteolytic resistance of W3R6, D-amino acids were incorporated into its sequence by specific amino acid substitution or whole sequence substitution according to the specificity of the cleavage site. In this study, partially substituted analog W3R6 and completely substituted D-enantiomer D-W3R6 were synthesized. The resistance of W3R6 and D-W3R6 to cleavage by the tested protease increased, particularly of D-W3R6. The antimicrobial activity of W3R6 was almost the same as that of the parent peptide W3R6, but the antimicrobial activity of D-W3R6 was slightly decreased. The hemolytic activity of both W3R6 and D-W3R6 was negligible. The CD spectrum of D-W3R6 exhibited symmetry with that of W3R6 in a membrane-mimetic environment. The membrane interaction between the D-amino acid substituted analogs and a real/mimic bacterial cell membrane was examined. The outer membrane depolarization, inner membrane permeability and dye leakage in three types of liposomes treated with W3R6 and D-W3R6 were not obviously different from W3R6, which could be due to the similar physical and chemical properties. In addition, these three peptides showed the binding ability with LPS micelles detected by ITC, and their ability to disrupt the LPS micelles was examined by DLS experiment and even neutralize the surface negative charge of E. coli cells. These results suggest that W3R6 is a promising antibiotic molecule.
抗菌肽 W3R6 源自 chensinin-1b，具有成为新型抗生素的潜力。然而，W3R6 容易被蛋白酶切割，这限制了其治疗应用。为了提高 W3R6 的抗蛋白酶水解能力，根据切割位点的特异性，通过特定氨基酸取代或整个序列取代将 D-氨基酸引入其序列中。在这项研究中，合成了部分取代的类似物 W3R6 和完全取代的 D-对映体 D-W3R6。W3R6 和 D-W3R6 对测试蛋白酶的切割的抗性增加，特别是 D-W3R6。W3R6 的抗菌活性与亲本肽 W3R6 几乎相同，但 D-W3R6 的抗菌活性略有降低。W3R6 和 D-W3R6 的溶血活性可以忽略不计。在模拟膜环境中，D-W3R6 的 CD 谱与 W3R6 的 CD 谱具有对称性。研究了 D-氨基酸取代类似物与真实/模拟细菌细胞膜之间的膜相互作用。用 W3R6 和 D-W3R6 处理的三种类型脂质体中外膜去极化、内膜通透性和染料渗漏与 W3R6 没有明显不同，这可能是由于它们具有相似的物理和化学性质。此外，这些三种肽都显示出与 LPS 胶束的结合能力，通过 ITC 检测到，并用 DLS 实验检查它们破坏 LPS 胶束的能力，甚至中和大肠杆菌细胞表面的负电荷。这些结果表明 W3R6 是一种有前途的抗生素分子。
