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Publication Abstract from PubMed

Dimethylsulfoniopropionate (DMSP) is an important marine anti-stress compound, with key roles in global nutrient cycling, chemotaxis and, potentially, climate regulation. Recently, diverse marine Actinobacteria, alpha- and gamma-proteobacteria were shown to initiate DMSP synthesis via the methionine (Met) S-methyltransferase enzyme (MmtN), generating S-methyl-Met (SMM). Here we characterize a roseobacterial MmtN, providing structural and mechanistic insights into this DMSP synthesis enzyme. We propose that MmtN uses the proximity and desolvation mechanism for Met S-methylation with two adjacent MmtN monomers comprising the Met binding site. We also identify diverse functional MmtN enzymes in potentially symbiotic archaeal Candidatus Woesearchaeota and Candidate Phyla Radiation (CPR) bacteria, and the animalcule Adineta steineri, not anticipated to produce SMM and/or DMSP. These diverse MmtN enzymes, alongside the larger plant MMT enzyme with an N-terminus homologous to MmtN, likely utilize the same proximity and desolvation mechanism. This study provides important insights into the catalytic mechanism of SMM and/or DMSP production, and proposes roles for these compounds in secondary metabolite production, and SMM cycling in diverse organisms and environments.

Insights into methionine S-methylation in diverse organisms.,Peng M, Li CY, Chen XL, Williams BT, Li K, Gao YN, Wang P, Wang N, Gao C, Zhang S, Schoelmerich MC, Banfield JF, Miller JB, Le Brun NE, Todd JD, Zhang YZ Nat Commun. 2022 May 26;13(1):2947. doi: 10.1038/s41467-022-30491-5. PMID:35618717^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.