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Bacterial SBP56 identified as a Cu-dependent methanethiol oxidase widely distributed in the biosphere

DOI: 10.1038/ismej.2017.148 DOI Help

Authors: Özge Eyice (University of Warwick; Queen Mary University of London) , Nataliia Myronova (University of Warwick) , Arjan Pol (Radboud University) , Ornella Carrión (University of East Anglia) , Jonathan D. Todd (University of East Anglia) , Tom J. Smith (Sheffield Hallam University) , Stephen J. Gurman (University of Leicester) , Adam Cuthbertson (University of Warwick) , Sophie Mazard (University of Warwick) , Monique Ash Mennink-Kersten (Radboud University) , Timothy D. H. Bugg (University of Warwick) , Karl kristoffer Andersson (University of Oslo) , Andrew W. B. Johnston (University of East Anglia) , Huub J. M. Op Den Camp (Radboud University) , Hendrik Schafer (University of Warwick)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Isme Journal , VOL 12

State: Published (Approved)
Published: October 2017
Diamond Proposal Number(s): 8769

Open Access Open Access

Abstract: Oxidation of methanethiol (MT) is a significant step in the sulfur cycle. MT is an intermediate of metabolism of globally significant organosulfur compounds including dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS), which have key roles in marine carbon and sulfur cycling. In aerobic bacteria, MT is degraded by a MT oxidase (MTO). The enzymatic and genetic basis of MT oxidation have remained poorly characterized. Here, we identify for the first time the MTO enzyme and its encoding gene (mtoX) in the DMS-degrading bacterium Hyphomicrobium sp. VS. We show that MTO is a homotetrameric metalloenzyme that requires Cu for enzyme activity. MTO is predicted to be a soluble periplasmic enzyme and a member of a distinct clade of the Selenium-binding protein (SBP56) family for which no function has been reported. Genes orthologous to mtoX exist in many bacteria able to degrade DMS, other one-carbon compounds or DMSP, notably in the marine model organism Ruegeria pomeroyi DSS-3, a member of the Rhodobacteraceae family that is abundant in marine environments. Marker exchange mutagenesis of mtoX disrupted the ability of R. pomeroyi to metabolize MT confirming its function in this DMSP-degrading bacterium. In R. pomeroyi, transcription of mtoX was enhanced by DMSP, methylmercaptopropionate and MT. Rates of MT degradation increased after pre-incubation of the wild-type strain with MT. The detection of mtoX orthologs in diverse bacteria, environmental samples and its abundance in a range of metagenomic data sets point to this enzyme being widely distributed in the environment and having a key role in global sulfur cycling.

Diamond Keywords: Bacteria; Enzymes

Subject Areas: Biology and Bio-materials, Chemistry

Instruments: B18-Core EXAFS

Added On: 06/11/2017 13:57


Discipline Tags:

Biochemistry Genetics Chemistry Life Sciences & Biotech

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) Extended X-ray Absorption Fine Structure (EXAFS)