ExplorEnz: EC 2.4.2.21

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2.4.2.21

Accepted name:

nicotinate-nucleotide—dimethylbenzimidazole phosphoribosyltransferase

Reaction:

β-nicotinate D-ribonucleotide + 5,6-dimethylbenzimidazole = nicotinate + α-ribazole 5′-phosphate

For diagram of the enzyme’s role in corrin biosynthesis, click here

Glossary:

α-ribazole 5′-phosphate = N¹-(5-phospho-α-D-ribosyl)-5,6-dimethylbenzimidazole

Other name(s):

nicotinate mononucleotide-dimethylbenzimidazole phosphoribosyltransferase; nicotinate ribonucleotide:benzimidazole (adenine) phosphoribosyltransferase; nicotinate-nucleotide:dimethylbenzimidazole phospho-D-ribosyltransferase; CobT; nicotinate mononucleotide (NaMN):5,6-dimethylbenzimidazole phosphoribosyltransferase

Systematic name:

nicotinate-nucleotide:5,6-dimethylbenzimidazole phospho-D-ribosyltransferase

Comments:

Also acts on benzimidazole, and the clostridial enzyme acts on adenine to form 7-α-D-ribosyladenine 5′-phosphate. The product of the reaction, α-ribazole 5′-phosphate, forms part of the corrin-biosynthesis pathway and is a substrate for EC 2.7.8.26, adenosylcobinamide-GDP ribazoletransferase [4]. It can also be dephosphorylated to form α-ribazole by the action of EC 3.1.3.73, α-ribazole phosphatase.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 37277-76-2

References:

1.	Friedmann, H.C. Partial purification and properties of a single displacement trans-N-glycosidase. J. Biol. Chem. 240 (1965) 413–418. [PMID: 14253445]
2.	Friedmann, H.C. and Fyfe, J.A. Pseudovitamin B₁₂ biosynthesis. Enzymatic formation of a new adenylic acid, 7-α-D-ribofuranosyladenine 5′-phosphate. J. Biol. Chem. 244 (1969) 1667–1671. [PMID: 5780835]
3.	Fyfe, J.A. and Friedmann, H.C. Vitamin B₁₂ biosynthesis. Enzyme studies on the formation of the α-glycosidic nucleotide precursor. J. Biol. Chem. 244 (1969) 1659–1666. [PMID: 4238408]
4.	Cameron, B., Blanche, F., Rouyez, M.C., Bisch, D., Famechon, A., Couder, M., Cauchois, L., Thibaut, D., Debussche, L. and Crouzet, J. Genetic analysis, nucleotide sequence, and products of two Pseudomonas denitrificans cob genes encoding nicotinate-nucleotide: dimethylbenzimidazole phosphoribosyltransferase and cobalamin (5′-phosphate) synthase. J. Bacteriol. 173 (1991) 6066–6073. [DOI] [PMID: 1917841]
5.	Cheong, C.G., Escalante-Semerena, J.C. and Rayment, I. Structural investigation of the biosynthesis of alternative lower ligands for cobamides by nicotinate mononucleotide: 5,6-dimethylbenzimidazole phosphoribosyltransferase from Salmonella enterica. J. Biol. Chem. 276 (2001) 37612–37620. [DOI] [PMID: 11441022]
6.	Cheong, C.G., Escalante-Semerena, J.C. and Rayment, I. Capture of a labile substrate by expulsion of water molecules from the active site of nicotinate mononucleotide:5,6-dimethylbenzimidazole phosphoribosyltransferase (CobT) from Salmonella enterica. J. Biol. Chem. 277 (2002) 41120–41127. [DOI] [PMID: 12101181]

[EC 2.4.2.21 created 1972]