Structural and biochemical characterization of Rv0187, an O-methyltransferase from Mycobacterium tuberculosis

Abstract

Catechol O-methyltransferase (COMT) is widely distributed in nature and installs a methyl group onto one of the vicinal hydroxyl groups of a catechol derivative. Enzymes belonging to this family require two cofactors for methyl transfer: S-adenosyl-l-methionine as a methyl donor and a divalent metal cation for regiospecific binding and activation of a substrate. We have determined two high-resolution crystal structures of Rv0187, one of three COMT paralogs from Mycobacterium tuberculosis , in the presence and absence of cofactors. The cofactor-bound structure clearly locates strontium ions and S-adenosyl-l-homocysteine in the active site, and together with the complementary structure of the ligand-free form, it suggests conformational dynamics induced by the binding of cofactors. Examination of in vitro activities revealed promiscuous substrate specificity and relaxed regioselectivity against various catechol-like compounds. Unexpectedly, mutation of the proposed catalytic lysine residue did not abolish activity but altered the overall landscape of regiospecific methylation.

Protein kinase J regulates Rv0642c expression and sensitivity to rifampicin of mycobacteria

“…The mmaA4 phosphorylation by PknJ has been shown by Phospho-chip analysis of peptide phosphorylation by rPknJ (Jang et al, 2010). The Catechol O-methyltransferase (COMT) is transferred the methyl group onto hydroxyl groups of a catechol and enhance the biological significance in mycobacteria (Lee et al, 2019). The mmaA4 gene is present in pathogenic mycobacteria and their homologs are in nonpathogenic strains according to their genome data base.…”

The Gut Microbiota Impact Cancer Etiology through “Phase IV Metabolism” of Xenobiotics and Endobiotics

“…Gut microbial COMTs are also poised to impact hormone bioavailability and disease etiology. After phase I metabolism, it is reasonable to expect that hydroxylated estrogens will serve as substrates for gut microbial COMTs, which are abundant and, like host COMTs, methylate catecholamines and catechol-estrogens (22). We speculate that interindividual differences in gut microbial COMTs may influence the circulating levels of drugs and endobiotics and, in the case of estrogens, would contribute to an individual's total level of hormone.…”

“…Dietary exposure to PhIP has been implicated in the etiology of cancer in humans (24). During phase I metabolism PhIP is oxidized via cytochrome P4501A2 (CYP1A2) enzymes to a hydroxylated intermediate, N-OH-PhIP (22). N-OH-PhIP, which is itself mutagenic, can be converted to a more biologically reactive form via phase II metabolizing enzymes, primarily the acetyltransferases or sulfotransferases (22).…”

“…During phase I metabolism PhIP is oxidized via cytochrome P4501A2 (CYP1A2) enzymes to a hydroxylated intermediate, N-OH-PhIP (22). N-OH-PhIP, which is itself mutagenic, can be converted to a more biologically reactive form via phase II metabolizing enzymes, primarily the acetyltransferases or sulfotransferases (22). The esterification generates electrophilic O-sulfonyl and O-acetyl esters, which bind DNA and cellular proteins (25).…”

Modification of the Pseudomonas aeruginosa toxin 2‐heptyl‐1‐hydroxyquinolin‐4(1H)‐one and other secondary metabolites by methyltransferases from mycobacteria

“…Mycobacteria have previously been reported to modify phenolic and catecholic compounds by Omethylation [26][27][28]. In 2016, inactivation of a pyridobenzimidazole-type antimycobacterial compound by N-methylation, catalyzed by the methyltransferase Rv0560c of M. tuberculosis, has been described as novel mode of antimicrobial resistance [29].…”