近日,国际著名杂志Nature在线刊登了国外研究人员的最新研究成果“Structure of a methyl-coenzyme M reductase from Black Sea mats that oxidize methane anaerobically。”,文章中,作者揭示了一种甲烷氧化酶的晶体结构。
喜甲烷古细菌和硫酸盐还原细菌中负责甲烷的“厌氧氧化”的酶,被认为是甲基-辅酶M还原酶(MCR)的一个同源物,后者催化产甲烷古细菌中的甲烷生成步骤。现在,研究人员从来自含有ANME-1类古细菌的黑海“藻苔垫”的一个环境样本中结晶出了一种MCR酶。该结构显示了辅酶M和辅酶B是怎样与金属酶相结合的,而ANME-1 MCR和产甲烷MCR结构之间的差别可帮助解释这些同源蛋白不同的酶活性。(生物谷Bioon.com)
doi:10.1038/nature10663
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Structure of a methyl-coenzyme M reductase from Black Sea mats that oxidize methane anaerobically
Seigo Shima, Martin Krueger, Tobias Weinert, Ulrike Demmer, Jörg Kahnt, Rudolf K. Thauer & Ulrich Ermler
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 bacteria1, 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 archaea3, 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 sulphate4. Crystals grown from the heterogeneous sample diffract to 2.1 Å resolution and consist of a single ANME-1 MCR 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-1 MCR and methanogenic MCR include a F430 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.