title: The active site structure of the calcium-containing quinoprotein methanol dehydrogenase.
abstract: Pyrroloquinoline quinone (PQQ), widely found in nature, serves as the redox cofactor in bacterial methanol dehydrogenase (MEDH), a heterotetrameric enzyme that oxidizes methanol to formaldehyde. The refined structure of MEDH at 2.4-A resolution, based on recently obtained amino acid sequence data, reveals that the PQQ, located in a central channel of the disk-shaped protein, is sandwiched between a Trp side chain and a very unusual vicinal disulfide. A Ca2+ ion forms a bridge between PQQ and the protein molecule, very close to a putative substrate binding pocket. The vicinal disulfide may form during PQQ incorporation and possibly act to hold the latter in place.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110.
authors.forename: S
authors.initials: S
authors.lastname: White
authors.forename: G
authors.initials: G
authors.lastname: Boyd
authors.forename: F S
authors.initials: FS
authors.lastname: Mathews
authors.forename: Z X
authors.initials: ZX
authors.lastname: Xia
authors.forename: W W
authors.initials: WW
authors.lastname: Dai
authors.forename: Y F
authors.initials: YF
authors.lastname: Zhang
authors.forename: V L
authors.initials: VL
authors.lastname: Davidson
mesh_terms: D000429:Alcohol Oxidoreductases / Q000648:ultrastructure*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000648:ultrastructure; D001665:Binding Sites; D002135:Calcium-Binding Proteins / Q000648:ultrastructure; D018360:Crystallography, X-Ray; D006090:Gram-Negative Bacteria / Q000201:enzymology*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D045542:PQQ Cofactor; D017434:Protein Structure, Tertiary; D015363:Quinolones / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D002135:Calcium-Binding Proteins; D015363:Quinolones; D045542:PQQ Cofactor; D000429:Alcohol Oxidoreductases; C019641:alcohol dehydrogenase (acceptor)