The Evolutionary Origin and Potential of Newly Recruited Enzymes

新招募的酶的进化起源和潜力

基本信息

批准号：
8055628
负责人：
SHELLEY D. COPLEY
金额：
$ 9.57万
依托单位：
UNIVERSITY OF COLORADO
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-05-15 至 2011-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8055628
关键词：
Active Sites Address Affect Agriculture Animal Model Antibiotic Resistance Antibiotics Bacteria Benign Binding Biochemical Bioremediations Catalysis Cells Chemicals Chlorine Cleaved cell Degradation Pathway Development Dioxygenases Elements Engineering Enzymes Escherichia coli Evolution Family Genetic Genomics Glutathione Household Human Hydrogen Hydroxylation Industry Iron Knowledge Life Metabolic Pathway Methods Microbe Mutation Outcome Oxidoreductase Pathway interactions Pentachlorophenol Pentachlorophenol monooxygenase Pharmacologic Substance Phenol 2-monooxygenase Play Process Proteins Quinone Reductases Reaction Recruitment Activity Resistance Role Scientist Soil Source Staging Structure Sulfur System Toxin Work catalyst chemical reaction chemical release dehalogenation design enzyme activity improved interest member microorganism novel pollutant protein structure function public health relevance

项目摘要

DESCRIPTION (provided by applicant): The evolution of enzymes was a critical element of the emergence of life on Earth and its subsequent divergence to occupy a vast range of ecological niches. Most enzymes have impressive catalytic capabilities that have been honed over 3.8 billion years of evolution. We are interested in the early stages of evolution of new enzymes. This application addresses enzymes that appear to have been recently recruited to serve new functions in the pathway for degradation of pentachlorophenol (PCP) in Sphingobium chlorophenolicum, a bacterium isolated from soil heavily contaminated with PCP. S. chlorophenolicum appears to have patched together a poorly functioning pathway for degradation of PCP using enzymes from at least two previously existing pathways. This experimental system provides us with a window on the evolution of a new metabolic pathway at a very early stage in the process. This application focuses on the initial three enzymes in the pathway that limit the flux through the PCP degradation pathway. PCP hydroxylase catalyzes the hydroxylation of PCP to form the toxic intermediate, tetrachlorobenzoquinone (TCBQ). TCBQ reductase catalyzes the reduction of TCBQ to tetrachlorohydroquinone (TCHQ). TCHQ dehalogenase catalyzes two successive reductive dehalogenation reactions that remove chlorines, allowing the ring to be cleaved. Our aims are 1) to obtain structures of PCP hydroxylase and TCHQ dehalogenase; 2) to explore the evolutionary origin and a possible additional function of TCBQ reductase; 3) to evolve improved versions of all three enzymes; and 4) to determine how the improved enzymes affect the ability of the bacterium to degrade PCP. The outcome of this work will be a better understanding of the sources from which new enzymes can arise, and the quality of catalysis achieved during the initial stages of evolution of a new enzyme. PUBLIC HEALTH RELEVANCE: We will better understand the prospects for evolution of pathways to degrade toxic pollutants and the problems associated with development of antibiotic resistance by recruitment of enzymes that detoxify antibiotics. In addition, this work will inform efforts to engineer enzymes and bacteria to produce chemicals and pharmaceuticals or to degrade pollutants under environmentally benign conditions.

描述（由申请人提供）：酶的进化是地球上生命出现的关键要素及其随后的差异，以占据广泛的生态位。大多数酶具有令人印象深刻的催化能力，这些催化能力已超过38亿年。我们对新酶进化的早期阶段感兴趣。该应用程序介绍了最近似乎已招募的酶，以在氯酚氯苯酚中降解戊二醇（PCP）的途径中，这是从氯苯酚中，这是一种从严重污染的PCP污染的土壤中分离出来的细菌。氯酚链球菌似乎使用了至少两种先前现有途径的酶来修补pcp降解的功能较差的途径。这个实验系统为我们提供了一个在此过程中很早的阶段的新代谢途径演变的窗口。该应用集中在途径中限制PCP降解途径通量的途径中的最初三个酶。 PCP羟化酶催化PCP的羟基化形成有毒中间体四氯苯喹酮（TCBQ）。 TCBQ还原酶催化TCBQ还原为四氯当喹酮（TCHQ）。 TCHQ脱脂酶催化了两种连续的还原脱征反应，从而去除氯，从而使环被裂解。我们的目标是1）获得PCP羟化酶和TCHQ脱核酶的结构； 2）探索TCBQ还原酶的进化起源和可能的附加功能； 3）进化所有三种酶的版本； 4）确定改进的酶如何影响细菌降解PCP的能力。这项工作的结果将是对新酶可能产生的来源的更好理解，以及在新酶的最初阶段所达到的催化质量。公共卫生相关性：我们将更好地了解降解有毒污染物途径的前景，以及通过募集抗生素抗生素抗生素耐药性而与抗生素耐药性相关的问题。此外，这项工作将为设计酶和细菌生产化学物质和药物或在环境良性条件下降解污染物的努力提供帮助。