Discovery and characterization of biocatalysts for ribosomally encoded alpha-N-methylated peptide natural products

项目总结/摘要 自20世纪20年代发现青霉素以来，生物活性肽天然产物已被用作 抗生素、抗病毒剂、免疫抑制剂和抗癌剂。这些生物活性肽中的许多含有 骨架α-N-甲基化和/或大环化，因为这些剪裁显著改善了肽的结构。 药代动力学正如在重磅炸弹免疫抑制剂环孢菌素A中所见，α-N-甲基化肽具有 增加的结构刚性、蛋白水解抗性和膜渗透性。此外，环状α-N- 甲基化的肽能够以高亲和力结合大的平坦表面，使它们成为有吸引力的靶， 破坏蛋白质-蛋白质相互作用。尽管有这些优点，但低效的合成和体外方法仍然存在。 阻碍α-N-甲基化肽的生产、筛选和优化。此外，自然资源 酰胺骨架甲基化肽被认为完全限于非柔性的非核糖体肽 生物合成途径这项工作的目标是梳理出α-N-的机制和结构限制， 甲基化生物催化剂在我们新发现的核糖体编码的肽天然产物家族称为 borosins。我们的第一个目标是确定一个有效的生物活性模式系统编码的一个担子菌真菌 梳理硼素α-N-甲基化、N-到-C大环化和生物活性的规律和限制。我们 第二个目标集中在结构上不同的borosin家族成员，在那里我们将进行详细的动力学研究。 测量，以梳理出化学挑战α-N-甲基化的机制。我们还概述了 长期的愿景是开发研究担子菌中肽天然产物的方法， 我们努力梳理出borosin代谢物的潜在生物学作用。这项研究将创造一个多样化的 用于生物生产，筛选和优化遗传物质的灵活有效的催化剂工具箱 模板化的生物活性α-N-甲基化肽。

PROJECT SUMMARY / ABSTRACT Since the discovery of penicillin in the 1920s, bioactive peptide natural products have been used as antibiotic, antiviral, immunosuppressive, and anti-cancer agents. Many of these bioactive peptides harbor backbone α-N-methylations and/or macrocyclizations, since these tailorings significantly improve peptide pharmacokinetics. As seen in the blockbuster immunosuppressant cyclosporin A, α-N-methylated peptides have increased structural rigidity, proteolytic resistance, and membrane permeability. Additionally, cyclic α-N- methylated peptides are able to bind large, flat surfaces with high affinity, making them attractive targets for disrupting protein-protein interactions. Despite these advantages, inefficient synthetic and in vitro processes hinder the production, screening, and optimization of α-N-methylated peptides. In addition, natural sources of amide backbone-methylated peptides were thought to be completely limited to inflexible nonribosomal peptide biosynthetic pathways. The goal of this work is to tease out the mechanistic and structural constraints of α-N- methylating biocatalysts within our newly discovered ribosomally encoded peptide natural product family called the borosins. Our first objective identifies a potent bioactive model system encoded in a basidiomycete fungus to tease out the rules and limitations of borosin α-N-methylation, N-to-C macrocyclization, and bioactivity. Our second objective focuses on structurally distinct borosin family members, where we will perform detailed kinetic measurements to tease out the mechanism for chemically challenging α-N-methylation. We also outline our longer-term visions to develop methods for studying peptide natural products in basidiomycete fungi as well as our efforts to tease out the potential biological roles of borosin metabolites. This research will create a diverse toolbox of flexible and efficient catalysts for the biological production, screening, and optimization of genetically templated bioactive α-N-methylated peptides.