Structure of a methyl-coenzyme M reductase from Black Sea mats that oxidize methane anaerobically
Structure of a methyl-coenzyme M reductase from Black Sea mats that oxidize methane anaerobically
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DOI：
10.1038/nature10663
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发表时间：
2012-01-05
期刊：
影响因子：
64.8
通讯作者：
Ermler, Ulrich
中科院分区：
文献类型：
--
作者：
Shima, Seigo;Krueger, Martin;Ermler, Ulrich
甲烷(AOM)与硫酸盐的厌氧氧化是目前微生物学研究的一个领域，由甲烷营养古菌(ANME)和硫酸盐还原细菌(1，2)组成的联合体完成。甲烷营养古菌中活化甲烷的酶已被初步鉴定为催化产甲烷古菌中甲烷形成步骤的甲基辅酶M还原酶(MCR)的同系物(3，4)。在这里，我们报告了280 kDa异六聚体ANME-1 MCR络合物的X射线结构。它是从从黑海垫子上的潜水器收集的微生物中提纯的蛋白质集合中独特结晶出来的，该微生物催化AOM与硫酸盐(4)。从非均相样品中生长的晶体衍射分辨率达到2.1埃，由单一的ANME-1MCR布居组成，显示出很强的结晶选择能力。结构显示ANME-1 MCR与辅酶M和辅酶B形成复合体，表明产甲烷古菌和甲烷古菌的MCR具有相同的底物。ANME-1MCR和产甲烷MCR高度相似的结构之间的差异包括F-430修饰、富含半胱氨酸的补丁和翻译后氨基酸修饰模式的改变，这可能调节酶在不同生物环境中的功能。
The anaerobic oxidation of methane (AOM) with sulphate, an area currently generating great interest in microbiology, is accomplished by consortia of methanotrophic archaea (ANME) and sulphate-reducing bacteria(1,2). The enzyme activating methane in methanotrophic archaea has tentatively been identified as a homologue of methyl-coenzyme M reductase (MCR) that catalyses the methane-forming step in methanogenic archaea(3,4). Here we report an X-ray structure of the 280 kDa heterohexameric ANME-1 MCR complex. It was crystallized uniquely from a protein ensemble purified from consortia of microorganisms collected with a submersible from a Black Sea mat catalysing AOM with sulphate(4). Crystals grown from the heterogeneous sample diffract to 2.1 angstrom resolution and consist of a single ANME-1MCR population, demonstrating the strong selective power of crystallization. The structure revealed ANME-1 MCR in complex with coenzyme M and coenzyme B, indicating the same substrates for MCR from methanotrophic and methanogenic archaea. Differences between the highly similar structures of ANME-1MCR and methanogenic MCR include a F-430 modification, a cysteine-rich patch and an altered post-translational amino acid modification pattern, which may tune the enzymes for their functions in different biological contexts.