title: Structure of a methyl-coenzyme M reductase from Black Sea mats that oxidize methane anaerobically.
abstract: 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. 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. 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. 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 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.
authors: Max Planck Institute for Terrestrial Microbiology, Karl-Frisch-Strasse 10, D-35043 Marburg, Germany. shima@mpi-marburg.mpg.de
authors: Seigo
authors: S
authors: Shima
authors: Martin
authors: M
authors: Krueger
authors: Tobias
authors: T
authors: Weinert
authors: Ulrike
authors: U
authors: Demmer
authors: Jörg
authors: J
authors: Kahnt
authors: Rudolf K
authors: RK
authors: Thauer
authors: Ulrich
authors: U
authors: Ermler
mesh_terms: D000693:Anaerobiosis; D001105:Archaea / Q000201:enzymology* / Q000302:isolation & purification / Q000378:metabolism; D055162:Biocatalysis; D059038:Black Sea; D020134:Catalytic Domain; D003067:Coenzymes / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000378:metabolism; D005101:Expeditions; D008697:Methane / Q000378:metabolism*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D012623:Seawater / Q000382:microbiology*; D012767:Ships; D013431:Sulfates / Q000378:metabolism
chemical_list: D003067:Coenzymes; D013431:Sulfates; D010088:Oxidoreductases; C021572:methyl coenzyme M reductase; D003545:Cysteine; D008697:Methane