title: Comparative analysis of two types of methanol dehydrogenase from Methylophaga aminisulfidivorans MPT grown on methanol.
abstract: Two types of methanol dehydrogenase (MDH) were obtained from a novel marine methylotrophic bacterium, Methylophaga aminisulfidivorans MP(T), grown on methanol. Type I MDH consisted of two identical dimers of α (65.98 kDa) and β (7.58 kDa) subunits organized to form the α(2)β(2) tetramer. Type II MDH contained an additional MxaJ protein (27.86 kDa) and had more specific activity than type I MDH. The K(m) values of type I and II MDH for methanol under cytochrome c(L) reduction assay system were estimated to be 50.3 and 13.0 μM, respectively, and the isoelectric points of type I and II MDH were determined to be 5.4 and 5.8, respectively. The average molar ratios of α:β, α:MxaJ, and β:MxaJ in type II MDH were approximately 1:0.99, 1:0.41 and 1:0.42, respectively. Based on these results, the original conformation of the MDH of M. aminisulfidivorans MP(T) is most likely the α(2)β(2)-MxaJ complex. During purification, the lysozyme and freeze-thawing cell disruption method significantly increased the amount of type II MDH in the soluble fraction compared with strong physical disruption methods such as sonication and French Press.
authors.affiliation: Department of Environmental Engineering and BK21 Team for Biohydrogen Production, Chosun University, Gwangju, Republic of Korea.
authors.forename: Hee Gon
authors.initials: HG
authors.lastname: Kim
authors.forename: Gui Hwan
authors.initials: GH
authors.lastname: Han
authors.forename: Dockyu
authors.initials: D
authors.lastname: Kim
authors.forename: Jong-Soon
authors.initials: JS
authors.lastname: Choi
authors.forename: Si Wouk
authors.initials: SW
authors.lastname: Kim
mesh_terms: D000429:Alcohol Oxidoreductases / Q000737:chemistry*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D015698:Genomic Library; D007526:Isoelectric Point; D000432:Methanol / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D044147:Piscirickettsiaceae / Q000201:enzymology*; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary
chemical_list: D001426:Bacterial Proteins; D000429:Alcohol Oxidoreductases; C019641:alcohol dehydrogenase (acceptor); D000432:Methanol