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Comparative analysis of two types of methanol dehydrogenase from Methylophaga aminisulfidivorans MP T grown on methanol
Author(s) -
Kim Hee Gon,
Han Gui Hwan,
Kim Dockyu,
Choi JongSoon,
Kim Si Wouk
Publication year - 2012
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201000479
Subject(s) - methanol dehydrogenase , isoelectric point , tetramer , methanol , chromatography , chemistry , lysozyme , enzyme , sonication , malate dehydrogenase , biochemistry , organic chemistry
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. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)