Journal of Microbiology

Research Support, Non-U.S. Gov't

Characterization of Methylophaga sp. strain SK1 Cytochrome cL Expressed in Escherichia coli: Hee Gon Kim , Trong Nhat Phan , Tae Sa Jang , Moonjoo Koh , Si Wouk Kim; J. Microbiol. 2005;43(6):499-502.; DOI: https://doi.org/2299 [pii]

Abstract: Methylophaga sp. strain SK1 is a new restricted facultative methanol-oxidizing bacterium that was isolated from seawater. The aim of this study was to characterize the electron carriers involved in the methanol oxidation process in Methylophaga sp. strain SK1. The gene encoding cytochrome cL (mxaG) was cloned and the recombinant gene was expressed in Escherichia coli DH5 under strict anaerobic conditions. The recombinant cytochrome cL had the same molecular weight and absorption spectra as the wild-type cytochrome cL both in the reduced and oxidized forms. The electron flow rate from methanol dehydrogenase (MDH) to the recombinant cytochrome cL was similar to that from MDH to the wild-type cytochrome cL. These results suggest that recombinant cytochrome cL acts as a physiological primary electron acceptor for MDH.

Enzyme Activities Related to the Methanol Oxidation of Mycobacterium sp. strain JC1 DSM 3803: Youngtae Ro , Eungbin Kim , Youngmin Kim; J. Microbiol. 2000;38(4):209-217.

Abstract: Mycobacterium sp. strain JC1 DSM 3803 grown in methanol showed no methanol dehydrogenase or oxidase activities found in most methylotrophic bacteria and yeasts, respectively. Even though the methanol-grown cells exhibited a little methanol-dependent oxidation by cytochrome c-dependent methanol dehydrogenase and alcohol dehydrogenase, they were not the key enzymes responsible for the methanol oxidation of the cells, in that the cells contained no c-type cytochrome and the methanol oxidizing activity from the partially purified alcohol dehydrogenase was too low, respectively. In substrate switching experiments, we found that only a catalase-peroxidase among the three types of catalase found in glucose-grown cells was highly expressed in the methanol-grown cells and that its activity was relatively high during the exponential growth phase in Mycobacterium sp. JC1. Therefore, we propose that catalase-peroxidase is an essential enzyme responsible for the methanol metabolism directly or indirectly in Mycobacterium sp. JC1.

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