Structure of a Methyl-Coenzyme M Reductase From Black Sea Mats That Oxidize Methane Anaerobically

Nature. 2011 Nov 27;481(7379):98-101. doi: 10.1038/nature10663.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaerobiosis
  • Archaea / enzymology*
  • Archaea / isolation & purification
  • Archaea / metabolism
  • Biocatalysis*
  • Black Sea
  • Catalytic Domain
  • Coenzymes / chemistry
  • Coenzymes / metabolism
  • Crystallography, X-Ray
  • Cysteine / metabolism
  • Expeditions
  • Methane / metabolism*
  • Models, Molecular
  • Oxidation-Reduction
  • Oxidoreductases / chemistry*
  • Oxidoreductases / metabolism*
  • Protein Conformation
  • Seawater / microbiology*
  • Ships
  • Sulfates / metabolism

Substances

  • Coenzymes
  • Sulfates
  • Oxidoreductases
  • methyl coenzyme M reductase
  • Cysteine
  • Methane

Associated data

  • PDB/3SQG