Biochemical characterization of MmoS, a sensor protein involved in copper-dependent regulation of soluble methane monooxygenase.
Biochemical characterization of MmoS, a sensor protein involved in copper-dependent regulation of soluble methane monooxygenase.
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MmoS 的生化特征，MmoS 是一种传感器蛋白，参与可溶性甲烷单加氧酶的铜依赖性调节。
DOI：
10.1021/bi060693h
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Rosenzweig,AmyC
中科院分区：
文献类型：
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作者：
Ukaegbu,UchechiE;Henery,Shannon;Rosenzweig,AmyC
甲烷单加氧酶 (MMO) 在甲烷氧化细菌中催化甲烷氧化为甲醇。包括荚膜甲基球菌 (Bath) 在内的几种甲烷氧化菌菌株在铜与生物质比率较高时表达膜结合或颗粒 MMO (pMMO)，而当铜有限时则表达可溶性 MMO (sMMO)。这种“铜开关”的机制尚不清楚。 ThemmoSgene 位于 sMMO 操纵子的下游，编码一种传感器蛋白，该蛋白是双组分信号系统的一部分，并且已被提议在铜开关中发挥作用。来自M的MmoS。 capsulatus(Bath) 已被克隆、表达和纯化。纯化的蛋白质是分子量为 480 kDa 的四聚体。光谱表明MmoS含有黄素辅因子，通过荧光光谱和色谱分析鉴定为黄素腺嘌呤二核苷酸(FAD)。 MmoS 结合的 FAD（结合在 N 端 PAS−PAC 结构域内）的氧化还原电位在 pH 8.0 和 25 °C 下为 -290 ± 2 mV。尽管付出了巨大的努力，MmoS 仍无法加载 CuI 或 CuII，这表明 MmoS 不能直接感应铜。这些数据表明 MmoS 作为氧化还原传感器发挥作用，并为铜介导的 sMMO 表达调节提供了新的见解。
Methane monooxygenase (MMO) enzymes catalyze the oxidation of methane to methanol in methanotrophic bacteria. Several strains of methanotrophs, includingMethylococcus capsulatus(Bath), express a membrane-bound or particulate MMO (pMMO) at high copper-to-biomass ratios and a soluble MMO (sMMO) form when copper is limited. The mechanism of this “copper switch” is not understood. ThemmoSgene, located downstream of the sMMO operon, encodes a sensor protein that is part of a two-component signaling system and has been proposed to play a role in the copper switch. MmoS fromM. capsulatus(Bath) has been cloned, expressed, and purified. The purified protein is a tetramer of molecular mass 480 kDa. Optical spectra indicate that MmoS contains a flavin cofactor, identified as flavin adenine dinucleotide (FAD) by fluorescence spectroscopy and chromatographic analysis. The redox potential of the MmoS-bound FAD, which binds within the N-terminal PAS−PAC domains, is −290 ± 2 mV at pH 8.0 and 25 °C. Despite extensive efforts, MmoS could not be loaded with CuIor CuII, indicating that MmoS does not sense copper directly. These data suggest that MmoS functions as a redox sensor and provide new insight into the copper-mediated regulation of sMMO expression.