X-RAY CRYSTALLOGRAPHIC STUDIES OF METHANE MONOOXYGENASE

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。可溶性甲烷单加氧酶(SMMO)是甲烷氧化细菌中催化甲烷氧化为甲醇的四组分酶系。催化发生在羟基酶(MMOH)组成的a亚单位中的羧酸桥联的双核铁中心。动力学和光谱研究表明，偶联蛋白(MMOB)与MMOH的对接提高了反应速度，改变了双铁中心的光谱性质。这些变化的原因尚不清楚。MMOD是一种新发现的编码在sMMO操纵子中的蛋白质，它通过与MMOB竞争结合来改变MMOH双铁中心的光谱性质，与α亚基交联，并抑制羟基酶的活性。目前尚不清楚MMOD如何改变双铁中心的性质或抑制活性。目前的研究目的是确定MMOH-MMOB和MMOH-MMOD络合物的结构，并探索不同条件下MMOH的双铁中心的结构细节。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Soluble methane monooxygenase (sMMO) is a four-component enzyme system that catalyzes the oxidation of methane to methanol in methanotrophic bacteria. Catalysis occurs at a carboxylate-bridged dinuclear iron center in the a subunit of the hydroxylase (MMOH) component. Kinetic and spectroscopic studies have shown that the docking of the coupling protein (MMOB) with MMOH enhances the reaction rate and alters the spectroscopic properties of the diiron center. The reasons for these changes are unknown. MMOD, a newly discovered protein encoded in the sMMO operon, alters the spectroscopic properties of the MMOH diiron center, cross-links to the a subunit, and inhibits hydroxylase activity by competing with MMOB for binding. It is unknown how MMOD alters the properties of the diiron center or inhibits activity. Current studies are aimed at determining the structures of the MMOH-MMOB and MMOH-MMOD complexes and probing structural details of the diiron site of MMOH under various conditions.