The methyltransferase NmbA methylates the low-molecular weight thiol bacillithiol, and displays a specific structural architecture.

ABSTRACT: Low-molecular-weight (LMW) thiols maintain the cellular redox balance and protect cells against reactive species, heavy metals, toxins, and antibiotics. Despite having similar metabolic functions, structurally distinct LMW thiols are widespread in nature, with bacillithiol (BSH) being the predominant LMW thiol in bacteria. The LMW thiol N-methyl-BSH (N-Me-BSH) has been identified in the green sulfur bacterium Chlorobaculum tepidum, revealing the presence of a putative S-adenosyl-l-methionine (SAM)-dependent methyltransferase (MT), NmbA, which could catalyze the final biosynthetic step of N-Me-BSH. In this study, we report biochemical evidence for NmbA's specific function as an MT of the N-atom of the BSH cysteine moiety. We also present the crystal structure of NmbA, confirming that NmbA i

SUBMITTER: Hammerstad M 

PROVIDER: S-EPMC12719100 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature