NMR structure of the flavin domain from soluble methane monooxygenase reductase from Methylococcus capsulatus (Bath).
Soluble methane monooxygenase (sMMO) catalyzes the hydroxylation of methane by dioxygen to methanol, the first step in carbon assimilation by methanotrophs. This multicomponent system transfers electrons from NADH through a reductase component to the non-heme diiron center in the hydroxylase where O(2) is activated. The reductase component comprises three distinct domains, a [2Fe-2S] ferredoxin domain along with FAD- and NADH-binding domains. We report the solution structure of the reduced 27.6 kDa FAD- and NADH-binding domains (MMOR-FAD) of the reductase from Methylococcus capsulatus (Bath). The FAD-binding domain consists of a six-stranded antiparallel beta-barrel and one alpha-helix, with the first 10 N-terminal residues unstructured. In the interface between the two domains, the FAD cofactor is tightly bound in an unprecedented extended conformation. The NADH-binding domain consists of a five-stranded parallel beta-sheet with four alpha-helices packing closely around this sheet. MMOR-FAD is structurally homologous to other FAD-containing oxidoreductases, and we expect similar structures for the FAD/NADH-binding domains of reductases that occur in other multicomponent monooxygenases.
Chatwood
Lisa L
LL
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA.
Müller
Jens
J
Gross
John D
JD
Wagner
Gerhard
G
Lippard
Stephen J
SJ
D000595:Amino Acid Sequence; D001665:Binding Sites; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry / Q000378:metabolism; D005415:Flavins / Q000737:chemistry* / Q000378:metabolism*; D020619:Methylococcus capsulatus / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009243:NAD / Q000737:chemistry / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D010105:Oxygenases / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D012995:Solubility
D005415:Flavins; D009243:NAD; D005182:Flavin-Adenine Dinucleotide; D010088:Oxidoreductases; D010105:Oxygenases; C021555:methane monooxygenase