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：
7532107
负责人：
SHELLEY D. COPLEY
金额：
$ 29.24万
依托单位：
UNIVERSITY OF COLORADO
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-07-01 至 2012-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7532107
关键词：
Active Sites Address Affect Agriculture Animal Model Antibiotic Resistance Antibiotics Bacteria Benign Binding Biochemical Bioremediations Catalysis Cells Chemicals Chlorine Cleaved cell Condition 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 NAD(P)H Dehydrogenase (Quinone)Outcome Oxidoreductase Pathway interactions Pentachlorophenol Pentachlorophenol monooxygenase Pharmacologic Substance Phenol 2-monooxygenase Play Process Proteins Public Health Quinone Reductases Range Rate 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

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及其随后分化以占据广泛生态位的关键要素。大多数酶都具有令人印象深刻的催化能力，这些能力经过 38 亿年的进化磨练。我们对新酶进化的早期阶段感兴趣。该应用解决了最近被招募来在氯酚鞘氨醇（一种从被五氯苯酚严重污染的土壤中分离出来的细菌）降解五氯苯酚（PCP）途径中发挥新功能的酶的研究。氯酚链球菌似乎利用至少两条先前存在的途径中的酶将功能较差的五氯苯酚降解途径拼凑在一起。该实验系统为我们提供了一个在该过程的早期阶段了解新代谢途径进化的窗口。本应用重点关注途径中限制五氯苯酚降解途径通量的前三种酶。五氯苯酚羟化酶催化五氯苯酚羟基化形成有毒中间体四氯苯醌（TCBQ）。 TCBQ 还原酶催化 TCBQ 还原为四氯氢醌 (TCHQ)。 TCHQ 脱卤酶催化两个连续的还原脱卤反应，去除氯，使环裂解。我们的目标是1）获得PCP羟化酶和TCHQ脱卤酶的结构； 2）探索TCBQ还原酶的进化起源和可能的附加功能； 3) 进化出所有三种酶的改进版本； 4) 确定改进的酶如何影响细菌降解五氯苯酚的能力。这项工作的结果将是更好地了解新酶的产生来源，以及新酶进化的初始阶段所达到的催化质量。公共卫生相关性：我们将更好地了解有毒污染物降解途径的进化前景，以及通过招募抗生素解毒酶而产生抗生素耐药性相关的问题。此外，这项工作将为改造酶和细菌以生产化学品和药物或在环境友好的条件下降解污染物的努力提供信息。