A mechanism for bacterial transformation of dimethylsulfide to dimethylsulfoxide: a missing link in the marine organic sulfur cycle

Ian Lidbury, Eileen Kröber, Zhidong Zhang, Yijun Zhu, J. Colin Murrell, Yin Chen, Hendrik Schäfer

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Abstract

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 oxidise DMS to DMSO using trimethylamine monooxygenase (Tmm). Purified Tmm oxidises 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.
Original languageEnglish
Pages (from-to)2754–2766
Number of pages13
JournalEnvironmental Microbiology
Volume18
Issue number8
Early online date27 Jun 2016
DOIs
Publication statusPublished - Aug 2016

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