Lantibiotic biosynthetic enzymes and autoimmunity

描述（由申请人提供）：本研究提案的长期目标是深入了解细菌中抗生素生物合成的分子基础，这将作为设计新型抗生素的框架。生物合成组合化学技术的最新工作已经建立了细菌聚酮酶和非核糖体肽酶在产生具有抗生素能力的天然和非天然产物中的效用。我们寻求通过提供使用羊毛硫抗生素的框架来扩展治疗剂的生物合成生产的研究，羊毛硫抗生素是核糖体合成但后修饰的肽家族。这些羊毛硫抗生素的工程化是复杂的，因为肽前体中产生的任何修饰都可能影响其作为翻译后修饰酶的底物的功能，并损害该方法的有效性。为了描述翻译后修饰酶的底物要求，我们的目标是确定许多lantibiotic修饰酶的高分辨率晶体结构。这些酶的晶体结构将用于鉴定和设计位点特异性变体。我们将通过将结构与我们合作者实验室中生成的功能数据相关联来测试我们基于结构的假设。此外，我们将确定免疫成分的晶体结构，该成分保护产乳酸菌免受其自身产生的药物的作用。我们试图理解为什么序列几乎相同的硫醚抗生素利用没有同源性且大小差异很大的免疫组分。最后，我们将利用在研究计划的前面的组成部分中产生的机械和结构数据来设计新型羊毛硫抗生素的生产。在这最后一个目标，我们将寻求利用生物合成组合化学的原则来回答这个问题“可以从基于结构的原则设计新的羊毛硫氨酸轴承羊毛硫抗生素？"

DESCRIPTION (provided by applicant): The long-term goal of this research proposal is to provide insights into the molecular basis for antibiotic biosynthesis in bacteria, which will serve as a framework for the design of novel antibiotics. Recent work in biosynthetic combinatorial chemistry technology has already established the utility of bacterial polyketide synthases and nonribosomal peptide synthases in generating natural and un-natural products with antibiotic capabilities. We seek to extend the research of biosynthetic production of therapeutics by providing a framework for the use of lantibiotics, a family of ribosomally synthesized but post-translationally modified peptides. The engineering of these lantibiotics is complicated by the fact that any modification that are generated in the peptide precursor may affect its function as a substrate for the post-translational modification enzymes, and compromise the effectiveness of this approach. In order to delineate the substrate requirements for the post-translation modification enzyme, we aim to determine the high-resolution crystal structures of many of the lantibiotic modification enzymes. The crystal structures of these enzymes will be used to identify and design site-specific variants. We will test our structure-based hypothesis by correlating the structure with functional data generated in the laboratory of our collaborator. Additionally, we will determine the crystal structure of the immunity component that protects the lantibiotic-producing bacteria from the action of its self-produced drug. We seek to understand why lantibiotics that are nearly identical in sequence utilize immunity components that share no homology and vary drastically in size. Finally, we will utilize the mechanistic and structural data generated in the previous components of the research plan to engineer the production of novel lantibiotics. In this last aim, we will seek to utilize the principles of biosynthetic combinatorial chemistry to answer the question "Can novel lanthionine-bearing lantibiotics be designed from structure-based principles?"