Comparative analysis of two types of methanol dehydrogenase from Methylophaga aminisulfidivorans MP T grown on methanol

• Published in: Journal of basic microbiology Vol. 52; no. 2; pp. 141 - 149
• Main Authors: Kim, Hee Gon, Han, Gui Hwan, Kim, Dockyu, Choi, Jong‐Soon, Kim, Si Wouk
• Format: Journal Article
• Language: English
• Published: 01.04.2012
• ISSN: 0233-111X; 1521-4028
• DOI: 10.1002/jobm.201000479

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. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)