A mechanism for bacterial transformation of dimethylsulfide to dimethylsulfoxide: a missing link in the marine organic sulfur cycle.
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.
School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry, CV4 7AL, UK.
Ian
I
Lidbury
School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry, CV4 7AL, UK.
Eileen
E
Kröber
Institute of Microbiology, Xinjiang Academy of Agriculture Sciences, Urumqi, 830091, China.
Zhidong
Z
Zhang
School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry, CV4 7AL, UK.
Yijun
Y
Zhu
School of Environmental Sciences, University of East Anglia, Norwich Research Park, NR4 7TJ, Norwich, UK.
J Colin
JC
Murrell
School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry, CV4 7AL, UK.
Yin
Y
Chen
School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry, CV4 7AL, UK.
Hendrik
H
Schäfer
D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D052836:Heterotrophic Processes / Q000502:physiology; D008744:Methylamines / Q000378:metabolism; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000378:metabolism*; D041904:Roseobacter / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012623:Seawater / Q000382:microbiology; D013440:Sulfides / Q000737:chemistry*; D013455:Sulfur / Q000378:metabolism; D014169:Transformation, Bacterial / Q000502:physiology*
D008744:Methylamines; D013440:Sulfides; D013455:Sulfur; C027451:methylamine; D010105:Oxygenases; C043996:tertiary amine monooxygenase; C004784:dimethyl sulfide; D004121:Dimethyl Sulfoxide