抗微生物肽(AMP)是对抗对常规抗微生物药物具有抗性的病原体的有希望的候选物,因为它们通过涉及膜破坏的机制起作用。然而,AMP在临床环境中的使用受到限制,至少在某种程度上,与哺乳动物细胞相比,它们对蛋白水解降解的敏感性以及对病原微生物缺乏选择性。我们最近报道了以天然存在的α-螺旋AMPaurein1.2为模板的α-和β-肽寡聚体的设计。这些α/β-肽寡聚体比金黄蛋白1.2更蛋白水解稳定,并且具有使它们作为常规AMP的替代物具有吸引力的若干其它属性。这项研究描述了肽的理化性质对基于aurein1.2的α/β肽模拟物针对9种细菌的广谱活性的影响,真菌,和哺乳动物细胞系。我们使用偏最小二乘回归(PLSR)监督的机器学习模型来量化和可视化实验确定的物理化学性质之间的关系(例如,疏水性,charge,和螺旋度),并通过实验测量了149个成员的α/β肽文库中21种肽的细胞类型特异性活性。使用这种方法,我们确定了几种预测显示出增强的广谱选择性的肽,一种评估抗微生物活性相对于哺乳动物细胞毒性的措施,与金黄色葡萄球菌1.2相比。实验验证证明了高模型预测性能,和表征具有最高广谱选择性的化合物揭示了肽的疏水性,螺旋度,和螺旋刚性是广谱选择性的强大预测因子。从模型预测中鉴定出的最具选择性的肽在广谱选择性方面比金黄色葡萄球菌1.2提高了13倍以上,证明了使用PLSR模型鉴定含非标准氨基酸的肽的定量结构-功能关系的能力。总的来说,这项工作为螺旋抗菌α/β-肽的合理设计建立了可量化的指南,并确定了有希望的新的α/β-肽,相对于金黄色葡萄球菌1.2,其具有显着降低的哺乳动物毒性和改善的抗真菌和抗菌活性。
Antimicrobial peptides (AMPs) are promising candidates to combat pathogens that are resistant to conventional antimicrobial drugs because they operate through mechanisms that involve membrane disruption. However, the use of AMPs in clinical settings has been limited, at least in part, by their susceptibility to proteolytic degradation and their lack of selectivity toward pathogenic microbes vs mammalian cells. We recently reported on the design of α- and β-peptide oligomers structurally templated upon the naturally occurring α-helical AMP aurein 1.2. These α/β-peptide oligomers are more proteolytically stable than aurein 1.2 and have several other attributes that render them attractive as alternatives to conventional AMPs. This study describes the influence of peptide physicochemical properties on the broad-spectrum activity of aurein 1.2-based α/β-peptide mimics against nine bacterial, fungal, and mammalian cell lines. We used a partial least-squares regression (PLSR)-supervised machine learning model to quantify and visualize relationships between experimentally determined physicochemical properties (e.g., hydrophobicity, charge, and helicity) and experimentally measured cell-type-specific activities of 21 peptides in a 149-member α/β-peptide library. Using this approach, we identified several peptides that were predicted to exhibit enhanced broad-spectrum selectivity, a measure that evaluates antimicrobial activity relative to mammalian cell toxicity compared to aurein 1.2. Experimental validation demonstrated high model predictive performance, and characterization of compounds with the highest broad-spectrum selectivity revealed peptide hydrophobicity, helicity, and helical rigidity to be strong predictors of broad-spectrum selectivity. The most selective peptide identified from the model prediction has more than a 13-fold improvement in broad-spectrum selectivity than that of aurein 1.2, demonstrating the ability of using PLSR models to identify quantitative structure-function relationships for nonstandard amino acid-containing peptides. Overall, this work establishes quantifiable
guidelines for the rational design of helical antimicrobial α/β-peptides and identifies promising new α/β-peptides with significantly reduced mammalian toxicities and improved antifungal and antibacterial activities relative to aurein 1.2.