title: Membrane-associated quinoprotein formaldehyde dehydrogenase from Methylococcus capsulatus Bath.
abstract: A membrane-associated, dye-linked formaldehyde dehydrogenase (DL-FalDH) was isolated from the obligate methylotroph Methylococcus capsulatus Bath. The enzyme was the major formaldehyde-oxidizing enzyme in cells cultured in high (above 1 micromol of Cu per mg of cell protein) copper medium and expressing the membrane-associated methane monooxygenase. Soluble NAD(P)(+)-linked formaldehyde oxidation was the major activity in cells cultured in low-copper medium and expressing the soluble methane monooxygenase (Tate and Dalton, Microbiology 145:159-167, 1999; Vorholt et al., J. Bacteriol. 180:5351-5356, 1998). The membrane-associated enzyme is a homotetramer with a subunit molecular mass of 49,500 Da. UV-visible absorption, electron paramagnetic resonance, and electrospray mass spectrometry suggest the redox cofactor of the DL-FalDH is pyrroloquinoline quinone (PQQ), with a PQQ-to-subunit stochiometry of approximately 1:1. The enzyme was specific for formaldehyde, oxidizing formaldehyde to formate, and utilized the cytochrome b(559/569) complex as the physiological electron acceptor.
authors.affiliation: Department of Microbiology, Iowa State University, 205 Science Building, Ames, IA 50011, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Zahn
authors.forename: D J
authors.initials: DJ
authors.lastname: Bergmann
authors.forename: J M
authors.initials: JM
authors.lastname: Boyd
authors.forename: R C
authors.initials: RC
authors.lastname: Kunz
authors.forename: A A
authors.initials: AA
authors.lastname: DiSpirito
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D002384:Catalysis; D002462:Cell Membrane / Q000201:enzymology; D003573:Cytochrome b Group / Q000378:metabolism; D005557:Formaldehyde / Q000378:metabolism; D020619:Methylococcus capsulatus / Q000201:enzymology*; D008969:Molecular Sequence Data; D045542:PQQ Cofactor; D045332:Photosystem II Protein Complex; D015363:Quinolones / Q000378:metabolism; D011809:Quinones / Q000378:metabolism
chemical_list: D003573:Cytochrome b Group; D045332:Photosystem II Protein Complex; D015363:Quinolones; D011809:Quinones; D005557:Formaldehyde; D045542:PQQ Cofactor; C019313:cytochrome b559; D000445:Aldehyde Oxidoreductases; C087006:formaldehyde dehydrogenase, glutathione-independent