Copper Acquisition by Methanotrophs.

描述(申请人提供)：甲烷是美国因人类活动而排放的第二大温室气体。由于甲烷在捕获辐射方面的有效性，它被认为比二氧化碳对环境的危害要大得多。甲烷氧化菌是一种革兰氏阴性细菌，可以代谢甲烷，并可能为甲烷的修复提供途径。在代谢甲烷的第一步中，甲烷氧化菌使用一种名为颗粒甲烷单加氧酶(PMMO)的完整膜蛋白将甲烷氧化为甲醇。PMMO是铜依赖的酶，因此甲烷氧化菌对铜的需求较高。在限制铜的条件下，一些甲烷氧化菌分泌一种类似天然产物的小分子，以高亲和力结合铜。这种名为甲氧基丁酸(MBN)的分子被重新内化到细胞内 它的铜负载形式，以满足电池的铜需求。这项拟议的研究将表征在两种不同的甲烷氧化菌中铜-MBN复合体重新内化所涉及的转运体。这项工作将深入了解甲烷代谢的一个关键要求，即为pMMO的辅因子获取铜的机制。此外，它将提供对甲烷营养细菌动态平衡的洞察。

DESCRIPTION (provided by applicant): Methane is the second most prevalent greenhouse gas emitted in the United States as a result of human activity. Because of methane's effectiveness at trapping radiation, it is considered significantly more deleterious to the environment than carbon dioxide. Methanotrophs are gram-negative bacteria that metabolize methane and may provide routes for the remediation of the gas. In the first step of metabolizing methane, methanotrophs use an integral membrane protein called particulate methane monooxygenase (pMMO) to oxidize methane to methanol. pMMO is copper-dependent enzyme, and thus methanotrophs have an elevated requirement for copper (Cu). Under conditions of limiting Cu, some methanotrophs secrete a small natural product-like molecule that binds Cu with high affinity. This molecule, called methanobactin (Mbn), is re- internalized into the cell in its Cu-loaded form to satisfy the cell's copper needs. The proposed research will characterize the transporter implicated in the re-internalization of the Cu-Mbn complex in two different methanotrophs. This work will provide insight into the mechanism by which a key requirement for methane metabolism, the acquisition of Cu for pMMO's cofactor, is fulfilled. Additionally, it will provide insight on methanotrophic bacterial homeostasis.