Metalloenzymes and metal homeostasis

项目摘要 这个研究项目的中心是甲烷氧化细菌的生物无机化学， 在它们代谢途径的第一步，将甲烷（一种强有力的温室气体）转化为甲醇。为 甲烷氧化菌是自然界中主要的甲烷汇，是减轻全球甲烷污染的有害影响的有前途的工具。 气候变暖对人类健康的影响，并可能被部署在一个由甲烷产生燃料和化学品的地方。 环保时尚。此外，一些甲烷氧化菌产生结合铜的天然产物， 正在研究中拟议的项目采取综合的生物化学，生物物理， 结构和遗传的方法来理解这些过程在分子水平上。 第一个项目涉及颗粒甲烷单加氧酶（pMMO）的结构和功能， 一种完整的膜，铜依赖酶，催化甲烷氧化为甲醇。尽管 pMMO晶体结构和一系列光谱数据的可用性， 铜的活性部位仍不清楚，底物、产物和还原剂结合的部位也不清楚。 阐明，阐明化学机制的所有先决条件。实验方法包括 具有高度不同序列的新pMMO的表征，脂质中pMMO的结构测定 保持酶活性的环境，以及天然甲烷氧化菌的遗传操作。结果 将导致对这种至关重要的金属酶的全面了解，并将进一步 了解同系物，如氨单加氧酶（AMO），气候变化的另一个贡献者。 第二个项目的重点是甲烷氧化菌素（Mbns），核糖体产生的， 由甲烷氧化菌分泌的改性天然产物，以从环境中除去铜。机械 生物合成和运输Mbns的基因编码在Mbn操纵子中，这些操纵子也存在于广泛的非- 甲烷氧化细菌，表明额外的功能和未开发的结构多样性。机械和 核心生物合成酶复合物的结构研究，含铁的MbnBC异二聚体，沿着 将进行其他生物合成蛋白质的表征。此外，其他操纵子的参与 将使用生物化学和体内策略来研究蛋白质在从MBN释放铜中的作用。采取 总之，这些结果将为天然产物的生物合成提供新的见解，并将影响这些天然产物的使用。 分子作为威尔逊病和其它铜代谢紊乱的治疗剂。

Project Summary This research program centers on the bioinorganic chemistry of methanotrophic bacteria, microbes that convert methane, a potent greenhouse gas, to methanol in the first step of their metabolic pathway. As the primary methane sink in nature, methanotrophs are promising tools to mitigate the deleterious effects of global warming on human health, and may be deployed to generate fuels and chemicals from methane in an environmentally-friendly fashion. Moreover, some methanotrophs produce copper-binding natural products that are under investigation as therapeutics. The proposed projects take an integrated biochemical, biophysical, structural, and genetic approach to understanding these processes on the molecular level. The first project addresses the structure and function of particulate methane monooxygenase (pMMO), an integral membrane, copper-dependent enzyme that catalyzes the oxidation of methane to methanol. Despite the availability of pMMO crystal structures and a range of spectroscopic data, the location and atomic details of the copper active site remain unclear, and the sites of substrate, product, and reductant binding have not been elucidated, all prerequisites for elucidating the chemical mechanism. The experimental approach involves characterization of new pMMOs with highly divergent sequences, structural determination of pMMOs in a lipid environment that maintains enzymatic activity, and genetic manipulation of native methanotrophs. The results will lead to a comprehensive understanding of this critically important metalloenzyme and will further understanding of homologs such as ammonia monooxygenase (AMO), another contributor to climate change. The second project focuses on methanobactins (Mbns), ribosomally produced, post-translationally modified natural products secreted by methanotrophs to scavenge copper from the environment. The machinery to biosynthesize and transport Mbns is encoded in Mbn operons, which are also present in a wide range of non- methanotrophic bacteria, suggesting additional functions and unexplored diversity in structure. Mechanistic and structural studies of the core biosynthetic enzyme complex, the iron-containing MbnBC heterodimer, along with characterization of other biosynthetic proteins will be conducted. In addition, the involvement of other operon proteins in release of copper from Mbn will be investigated using both biochemical and in vivo strategies. Taken together, the results will provide new insights into natural products biosynthesis and will impact the use of these molecules as therapeutics for Wilson disease and other disorders of copper metabolism.