Microbial catabolism of steroids, from enzymes to ecosystems

类固醇的微生物分解代谢，从酶到生态系统

• 批准号: 155184-2013
• 负责人: Mohn, William
• 金额: $ 5.03万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569428
• 关键词: Microbial; catabolism; steroids; enzymes; ecosystems

Microbial steroid catabolism plays important roles in biomass decomposition, decontamination of wastewaters, synthesis of drugs and pathogenesis. My Discovery Grant research program has made very significant advances in our understanding of steroid catabolism. The next phase of the program has the goals of (1) elucidating the poorly-understood initial steps of steroid degradation and (2) exploring the diversity, evolution and ecology of steroid catabolism. I hypothesize that the initial catabolic steps vary according to ecological niches and potentially play roles in microbe-host interactions. I will investigate the roles of cholesterol oxidases and hydroxysteroid dehydrogenases, including their relative importance for the use of membrane-associated versus free steroids by Rhodococcus jostii. This investigation will involve analysis of gene expression, production and characterization of mutant strains as well as enzyme expression and activity assays. More broadly, microbial genomic and metagenomic approaches offer exciting new potential to explore the diversity of microbial metabolism and ecology, but these approaches are severely hampered by the lack of functionally-characterized proteins, which leads to mis-annotation of genes. I will use a unique combination of bioinformatic and biochemical analyses in an iterative process to develop and expand a reference set of steroid catabolism genes/proteins. With this knowledge base, I will map the occurrence of steroid catabolism pathways across microbial taxa and different environments. Thusly, in microbial strains and in environmental DNA, I will identify novel genes and pathways that warrant biochemical investigation. Overall, this research program will make important advances in our mechanistic understanding of microbial steroid catabolism and in our understanding of the evolution and ecology of the pathways. This understanding will maximize our ability to exploit microbial steroid transformations for industrial and environmental processes and may open the door to a new paradigm for microbe-host interactions.

微生物甾体催化剂在生物质分解、废水净化、药物合成和致病等方面发挥着重要作用。我的发现补助金研究计划在我们对类固醇catastrophe的理解方面取得了非常重大的进展。该计划的下一阶段的目标是：（1）阐明类固醇降解的初始步骤，（2）探索类固醇降解的多样性，进化和生态学。我假设，最初的分解代谢步骤根据生态位而变化，并可能在微生物-宿主相互作用中发挥作用。我将研究胆固醇氧化酶和羟基类固醇脱氢酶的作用，包括它们的相对重要性，使用膜相关与自由类固醇的红球菌jostii。这项研究将涉及基因表达分析，突变菌株的生产和表征以及酶表达和活性测定。更广泛地说，微生物基因组学和宏基因组学方法为探索微生物代谢和生态学的多样性提供了令人兴奋的新潜力，但这些方法受到缺乏功能特征蛋白质的严重阻碍，这导致基因的错误注释。我将使用生物信息学和生物化学分析的独特组合，在一个迭代过程中开发和扩展类固醇categories基因/蛋白质的参考集。有了这个知识基础，我将绘制跨微生物类群和不同环境的类固醇catalysts途径的发生。因此，在微生物菌株和环境DNA中，我将确定新的基因和途径，保证生化研究。总的来说，这项研究计划将在我们对微生物类固醇catenorase的机制理解以及我们对途径的进化和生态学的理解方面取得重要进展。这种理解将最大限度地提高我们利用微生物类固醇转化工业和环境过程的能力，并可能为微生物-宿主相互作用的新范式打开大门。