Glycine betaine monooxygenase, an unusual Rieske-type oxygenase system, catalyzes the oxidative N-demethylation of glycine betaine in Chromohalobacter salexigens DSM 3043.

Glycine betaine monooxygenase, an unusual Rieske-type oxygenase system, catalyzes the oxidative N-demethylation of glycine betaine in Chromohalobacter salexigens DSM 3043. Appl Environ Microbiol. 2018 Apr 27;: Authors: Shao YH, Guo LZ, Zhang YQ, Yu H, Zhao BS, Pang HQ, Lu WD Abstract Although some bacteria, including Chromohalobacer salexigens DSM 3043, can use glycine betaine (hereafter referred to as GB) as the sole carbon and energy source, little information is available about the genes and their encoded proteins involved in the initial step of GB degradation pathway. In the present study, the results of conserved domain analysis, construction of in-frame deletion mutants, and in vivo functional complementation assay suggested that the open reading frames Csal_1004 and Csal_1005, designated bmoA and bmoB, may act as the terminal oxygenase and the ferredoxin reductase in a novel Rieske-type oxygenase system to convert GB to dimethylglycine in C. salexigens DSM 3043. To further verify their function, BmoA and BmoB were heterologously overexpressed in Escherichia coli, and 13C-nuclear magnetic resonance analysis revealed that dimethylglycine was accumulated in E. coli BL21(DE3) expressing BmoAB or BmoA. In addition, His-tagged BmoA and BmoB were individually purified to electrophoretic homogeneity and estimated to be a homotrimer and a monomer, respectively. In vitro biochemical analysis indicated that BmoB is an NADH-dependent flav...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research