Enzymatic Biodegradation of Chlorooxides

描述（由申请人提供）：氯氧化物（ClOx-）离子是人为的杀生物剂、漂白剂和氧化剂，由于其高溶解度和广泛用于农业、工业和军事，已成为饮用水和淡水环境的主要污染物。各种氯氧化物都被怀疑和记录的健康危害。以下建议将确定在蛋白质/酶水平上深入研究微生物ClOx解毒的可行性。美国环保署已将二氧化氯（CIO 2-）列入其主要饮用水标准清单，饮用水中的法定上限为0.8 mg/L。与慢性ClO 2暴露相关的健康风险包括儿童和婴儿的贫血和神经系统疾病。在其最近被鉴定为井水污染物后，高氯酸盐（CIO 4-）被添加到EPA的污染物候选清单中。它的全部健康影响目前正在由EPA和其他机构进行研究。为了应对氯氧化物的涌入，自然界已经进化出解毒甚至利用它们的机制。在过去十年中，已经分离出厌氧呼吸氯氧化物（包括CIO 4-、CIO 3-和CIO 2-）的微生物。传统的去除水中小离子的方法是昂贵的或非特异性的，因此氯氧化物的生物修复是一个新兴的生物工程目标。芳香去氯单胞菌是唯一一种具有测序基因组的（ClOx-）呼吸微生物，是生物化学研究的明显选择（J.D.科茨，加州大学伯克利分校）。此外，脱氯单胞菌属在纯培养物中的菌株中是独特的，因为它氧化不溶性烃，包括苯，一种主要的环境污染物和一种强有力的人类致癌物。我们寻求[1]分离、部分测序和鉴定D.芳香剂;[2]从宿主和异源表达系统中获得足够量的纯酶用于机械和X射线结构研究;[3]部分表征内源和表达的酶。这些目标为未来的机制，光谱，结构和蛋白质工程研究（ClOx-）解毒途径的这些组件奠定了基础。这项工作将是旨在开发生物修复系统和/或用于环境监测的酶基传感器的全球努力的一部分。

DESCRIPTION (provided by applicant): The chlorooxide (ClOx-) ions are anthropogenic biocides, bleaches, and oxidants that, because of their high solubility and ubiquitous use by agriculture, industry, and the military, have become major contaminants of drinking water and fresh water environments. The various chlorooxides are both suspected and documented health hazards. The following proposal will determine the feasibility of in-depth studies of microbe-based ClOx- detoxification at the protein/enzyme level. The U.S. EPA has included chlorite (CIO2-) on its list of Primary Drinking Water Standards, with a legally mandated upper limit of 0.8 mg/L in drinking water. Health risks associated with chronic CIO2- exposure include anemia and nervous system disorders in children and infants. After its recent identification as a well water contaminant, perchlorate (CIO4-) was added to the EPA's Contaminant Candidate List. Its full health effects are currently under study by the EPA and by others. In response to an influx of chlorooxides, nature has evolved mechanisms to detoxify and even exploit them. Microorganisms that anaerobically respire chlorooxides, including CIO4-, CIO3-, and CIO2-, have been isolated over the last decade. Traditional means of removing small ions from water are expensive or nonspecific, so bioremediation of chlorooxides is an emerging bioengineering goal. Dechloromonas aromatica, the only (ClOx-)-respiring microbe with a sequenced genome, is the obvious choice for biochemical study (J.D. Coates, University of California, Berkeley). Moreover, Dechloromonas is unique among strains in pure culture, in that it oxidizes intransigent hydrocarbons including benzene, a major environmental contaminant and a potent human carcinogen. We seek [1] to isolate, partially sequence, and identify the genes encoding (ClOx-)-metabolizing activities in D. aromatica; [2] to obtain sufficient quantities of pure enzymes for mechanistic and X-ray structural studies from the host and heterologous expression systems; and [3] to partially characterize the endogenous and expressed enzymes. These objectives set the stage for future mechanistic, spectroscopic, structural, and protein-engineering studies of these components of the (ClOx-) detoxification pathway. This work will be part of a more global effort aimed at developing bioremediation systems, and/or enzyme-based sensors for environmental monitoring.