trimethylamine monooxygenase (Tmm) oxidize DMS to DMSO.
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IRWVEYNEDAGNFTVTVHDHAKDSTYKEDFDHVICASGHFSTPNVPFYPGFDSFNGRVLH
AHDFRDAREFKGKDILILGASYSAEDIGSQCWKYGAKSITTSYRSAPMGFNWPDNWDEVP
ALEAVKGNTAFFADGTQKEVDAIIXCTGYKHFFSFLPDDLRLKTANRLAAADLYKGVVFA
HNPKMFYLGMQDQWFT260
| PMID | Title & Author | Abstract | Year | |
| 0 | 27114231 | A mechanism for bacterial transformation of dimethylsulfide to dimethylsulfoxide: a missing link in the marine organic sulfur cycle. Lidbury I, Kröber E, Zhang Z, Zhu Y, Murrell JC, Chen Y, Schäfer H. | The volatile organosulfur compound, dimethylsulfide (DMS), plays an important role in climate regulation and global sulfur biogeochemical cycles. Microbial oxidation of DMS to dimethylsulfoxide (DMSO) represents a major sink of DMS in surface seawater, yet the underlying molecular mechanisms and key microbial taxa involved are not known. Here, we reveal that Ruegeria pomeroyi, a model marine heterotrophic bacterium, can oxidize DMS to DMSO using trimethylamine monooxygenase (Tmm). Purified Tmm oxidizes DMS to DMSO at a 1:1 ratio. Mutagenesis of the tmm gene in R. pomeroyi completely abolished DMS oxidation and subsequent DMSO formation. Expression of Tmm and DMS oxidation in R. pomeroyi is methylamine-dependent and regulated at the post-transcriptional level. Considering that Tmm is present in approximately 20% of bacterial cells inhabiting marine surface waters, particularly the marine Roseobacter clade and the SAR11 clade, our observations contribute to a mechanistic understanding of biological DMSO production in surface seawater. | 2016 |
| 1 | 22540311 | Comparative genomics of methylated amine utilization by marine Roseobacter clade bacteria and development of functional gene markers (tmm, gmaS). Chen Y. | The marine Roseobacter clade bacteria comprise up to 20% of the microbial community in coastal surface seawater. Marine Roseobacter clade bacteria are known to catalyse some important biogeochemical transformations in marine carbon and sulfur cycles. Using a comparative genomic approach, this study revealed that many marine Roseobacter clade bacteria have the genetic potential to utilize methylated amines (MAs) as alternative nitrogen sources. These MAs represent a significant pool of dissolved organic carbon and nitrogen in the marine environment. The marine Roseobacter clade bacterial genomes also encode full sets of genes providing them with the potential to generate energy from complete oxidation of the methyl groups of MAs. Representative species of the marine Roseobacter clade were tested and their abilities to use MAs are directly linked to the presence in their genomes of genes encoding key enzymes involved in MA metabolism, including trimethylamine monooxygenase (tmm) and gamma-glutamylmethylamide synthetase (gmaS). These two genes were chosen as functional markers for detecting MA-utilizing marine Roseobacter clade bacteria in the environment. PCR primers targeting these two genes were designed and used successfully to retrieve corresponding gene sequences from MA-utilizing isolates of the marine Roseobacter clade, as well as directly from DNA extracted from surface seawater obtained from Station L4 off the coast of Plymouth, UK. Taken together, the results suggest that MAs may serve as important nitrogen and possibly energy sources for marine Roseobacter clade bacteria, which helps to explain their global success in the marine environment. | 2012 |
| 2 | 27997715 | Structural mechanism for bacterial oxidation of oceanic trimethylamine into trimethylamine N-oxide. Li CY, Chen XL, Zhang D, Wang P, Sheng Q, Peng M, Xie BB, Qin QL, Li PY, Zhang XY, Su HN, Song XY, Shi M, Zhou BC, Xun LY, Chen Y, Zhang YZ. | rimethylamine (TMA) and trimethylamine N-oxide (TMAO) are widespread in the ocean and are important nitrogen source for bacteria. TMA monooxygenase (Tmm), a bacterial flavin-containing monooxygenase (FMO), is found widespread in marine bacteria and is responsible for converting TMA to TMAO. However, the molecular mechanism of TMA oxygenation by Tmm has not been explained. Here, we determined the crystal structures of two reaction intermediates of a marine bacterial Tmm (RnTmm) and elucidated the catalytic mechanism of TMA oxidation by RnTmm. The catalytic process of Tmm consists of a reductive half-reaction and an oxidative half-reaction. In the reductive half-reaction, FAD is reduced and a C4a-hydroperoxyflavin intermediate forms. In the oxidative half-reaction, this intermediate attracts TMA through electronic interactions. After TMA binding, NADP+ bends and interacts with D317, shutting off the entrance to create a protected micro-environment for catalysis and exposing C4a-hydroperoxyflavin to TMA for oxidation. Sequence analysis suggests that the proposed catalytic mechanism is common for bacterial Tmms. These findings reveal the catalytic process of TMA oxidation by marine bacterial Tmm and first show that NADP+ undergoes a conformational change in the oxidative half-reaction of FMOs. | 2017 |
Lidbury I , Kr?Ber E , Zhang Z , et al. A mechanism for bacterial transformation of dimethylsulfide to dimethylsulfoxide: a missing link in the marine organic sulfur cycle[J]. Environmental Microbiology, 2016.