The effects of tryptophan and hydrophobicity on the structure and bioactivity of novel indolicidin derivatives with promising pharmaceutical potential
作者:Aaron P. Podorieszach、Heidi E. K. Huttunen-Hennelly
DOI:10.1039/b921248e
日期:——
In the current study, indolicidin, a known antimicrobial originally isolated from bovine neutrophils, was modified with respect to hydrophobicity and tryptophan content to maximize bioactivity, and minimize cytotoxicity. Since indolicidin contains five tryptophans (very hydrophobic) of its total 13 amino acids, alanine (mildly hydrophobic) was incrementally substituted in its place to generate five novel derivatives with decreasing hydrophobicity. Antimicrobial testing identified two active derivatives with minimum inhibitory concentrations in the 10−9 g mL−1 range against Candida albicans, as well as broad-spectrum activity against various other Gram-positive/negative pathogens in the 10−3–10−6 g mL−1 range. Cytotoxicity testing yielded minimum hemolytic concentrations of ∼3 × 10−3 g mL−1 for both active derivatives, resulting in hemolytic indices of >1.3 × 106 (peptide Δ45) and 3.6 × 105 (peptide Δ5) (improvements of >33 000-fold and ∼10 000-fold, respectively, compared to indolicidin). The potent antimicrobial activity and low cytotoxicity of these derivatives show promise as potential antibiotics.
在当前的研究中,indolicidin(一种最初从牛中性粒细胞中分离出来的已知抗菌剂)在疏水性和色氨酸含量方面进行了修饰,以最大限度地提高生物活性并最大限度地降低细胞毒性。由于 indolicidin 的 13 个氨基酸中含有 5 个色氨酸(高度疏水性),因此逐渐取代丙氨酸(轻度疏水性),生成了 5 种疏水性逐渐降低的新型衍生物。抗菌测试确定了两种活性衍生物,其对白色念珠菌的最低抑制浓度在 10−9 g mL−1 范围内,并且在 10−3–10−6 g 范围内对各种其他革兰氏阳性/阴性病原体具有广谱活性mL−1 范围。细胞毒性测试得出两种活性衍生物的最低溶血浓度为 ~3 × 10−3 g mL−1,导致溶血指数 >1.3 × 106(肽 Δ45)和 3.6 × 105(肽 Δ5)(改善 >33 000-与 indolicidin 相比,分别为 10 倍和 10 000 倍)。这些衍生物的有效抗菌活性和低细胞毒性显示出作为潜在抗生素的前景。