Reaction: glycerone phosphate + iminosuccinate = pyridine-2,3-dicarboxylate + 2 H2O + phosphate
For diagram of reaction, click here.
Glossary: quinolinate = pyridine-2,3-dicarboxylate
glycerone phosphate = dihydroxyacetone phosphate = 3-hydroxy-2-oxopropyl phosphate
Other name(s): NadA; QS; quinolinate synthetase
Systematic name: glycerone-phosphate:iminosuccinate alkyltransferase (cyclizing)
Comments: An iron-sulfur protein that requires a [4Fe-4S] cluster for activity [1]. Quinolinate synthase catalyses the second step in the de novo biosynthesis of NAD+ from aspartate in some bacteria, with EC 1.4.3.16 (L-aspartate oxidase) catalysing the first step and EC 2.4.2.19 [nicotinate-nucleotide diphosphorylase (carboxylating)] the third step. In Escherichia coli, two of the residues that are involved in the [4Fe-4S] cluster binding appear to undergo reversible disulfide-bond formation that regulates the activity of the enzyme [5].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:
References:
1. Ollagnier-de Choudens, S., Loiseau, L., Sanakis, Y., Barras, F. and Fontecave, M. Quinolinate synthetase, an iron-sulfur enzyme in NAD biosynthesis. FEBS Lett. 579 (2005) 3737-3743. [PMID: 15967443]
2. Katoh, A., Uenohara, K., Akita, M. and Hashimoto, T. Early steps in the biosynthesis of NAD in Arabidopsis start with aspartate and occur in the plastid. Plant Physiol. 141 (2006) 851-857. [PMID: 16698895]
3. Sakuraba, H., Tsuge, H., Yoneda, K., Katunuma, N. and Ohshima, T. Crystal structure of the NAD biosynthetic enzyme quinolinate synthase. J. Biol. Chem. 280 (2005) 26645-26648. [PMID: 15937336]
4. Rousset, C., Fontecave, M. and Ollagnier de Choudens, S. The [4Fe-4S] cluster of quinolinate synthase from Escherichia coli: Investigation of cluster ligands. FEBS Lett. 582 (2008) 2937-2944. [PMID: 18674537]
5. Saunders, A.H. and Booker, S.J. Regulation of the activity of Escherichia coli quinolinate synthase by reversible disulfide-bond formation. Biochemistry 47 (2008) 8467-8469. [PMID: 18651751]