Nicotinate-nucleotide--dimethylbenzimidazole phosphoribosyltransferase (MjCobT) (MjCobT)

Nicotinate-nucleotide--dimethylbenzimidazole phosphoribosyltransferase, commonly known as MjCobT, is an enzyme originating from the hyperthermophilic archaeon Methanocaldococcus jannaschii (UniProt Q58364). It catalyzes the condensation of nicotinate mononucleotide (NaMN) and 5,6-dimethylbenzimidazole (DMB) to produce alpha-ribazole-5'-phosphate, a critical intermediate in the late stages of Vitamin B12 (cobalamin) biosynthesis (PMID: 15939103). While M. jannaschii is not a pathogen, MjCobT is extensively studied in structural biology as a stable model for the CobT family of enzymes, which are vital for the survival and pathogenesis of bacteria such as Mycobacterium tuberculosis and Salmonella enterica (PMID: 10411894). Since humans do not possess the machinery to synthesize Vitamin B12 and must obtain it through diet, microbial CobT enzymes are considered promising targets for the development of narrow-spectrum antimicrobial agents. Current drug discovery efforts involving MjCobT focus on utilizing its crystal structure to design transition-state analogs and competitive inhibitors that can block the B12 pathway in infectious organisms.

Other names

CobT5,6-dimethylbenzimidazole phosphoribosyltransferaseDMB-PRTNaMN:DMB phosphoribosyltransferaseNicotinate-nucleotide:dimethylbenzimidazole phosphoribosyltransferase

Competitive inhibition of phosphoribosyltransferase activity to disrupt cobalamin biosynthesis.