Harmon Thomas W, Song Junming, Gulewicz Andrew J, Di Y Peter, Horne W Seth
Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15260, USA.
Chembiochem. 2025 Feb 3;26(5):e202400951. doi: 10.1002/cbic.202400951. Epub 2025 Jan 9.
The threat posed by bacteria resistant to common antibiotics creates an urgent need for novel antimicrobials. Non-ribosomal peptide natural products that bind Lipid II, such as vancomycin, represent a promising source for such agents. The fungal defensin plectasin is one of a family of ribosomally produced miniproteins that also exert antimicrobial activity via Lipid II binding. Made up entirely of canonical amino acids, these molecules are potentially more susceptible to degradation by protease enzymes than non-ribosomal counterparts. Here, we report the development of proteomimetic variants of plectasin through the systematic incorporation of artificial backbone connectivity in the domain. An iterative secondary-structure-based design scheme yields a variant with a tertiary fold indistinguishable from the prototype natural product, potent activity against Gram positive bacteria, and low mammalian cell toxicity. Backbone modification is shown to improve oxidative folding efficiency of the disulfide-rich scaffold as well as resistance to proteolytic hydrolysis. These results broaden the scope of design strategies toward protein mimetics as well as folds and biological functions possible in such agents.
对常见抗生素具有抗性的细菌所构成的威胁，迫切需要新型抗菌药物。与脂质II结合的非核糖体肽天然产物，如万古霉素，是这类药物的一个有前景的来源。真菌防御素plectasin是核糖体产生的小蛋白家族之一，它也通过与脂质II结合发挥抗菌活性。这些分子完全由标准氨基酸组成，与非核糖体对应物相比，可能更容易被蛋白酶降解。在此，我们报告了通过在结构域中系统引入人工主链连接来开发plectasin的蛋白质模拟变体。基于二级结构的迭代设计方案产生了一种变体，其三级折叠与原型天然产物难以区分，对革兰氏阳性菌具有强大活性，且对哺乳动物细胞毒性低。主链修饰显示可提高富含二硫键支架的氧化折叠效率以及对蛋白水解的抗性。这些结果拓宽了蛋白质模拟物的设计策略范围，以及这类药物可能具有的折叠和生物学功能。
