Reaction: 2 ATP + 2 L-glutamine + O2 + 2 FMN = 2 AMP + 2 diphosphate + indigoidine + 2 H2O + 2 FMNH2 (overall reaction)
(1) 2 ATP + 2 L-glutamine + 2 FMN = 2 AMP + 2 diphosphate + 2 3-amino-1,5-dihydropyridine-2,6-dione + FMNH2
(2) 2 3-amino-1,5-dihydropyridine-2,6-dione + O2 = indigoidine + 2 H2O (spontaneous)
For diagram of reaction, click here
Glossary: indigoidine = 3-(5-amino-2-hydroxy-6-oxo-1H-pyridin-3-yl)-5-iminopyridine-2,6-dione
Other name(s): bspA (gene name)
Systematic name: L-glutamine oxidoreductase/cyclase (3-amino-1,5-dihydropyridine-2,6-dione-forming)
Comments: The enzyme, found in a number of bacterial strains, is a non-ribosomal peptide synthase (NRPS). The enzyme forms 3-amino-1,5-dihydropyridine-2,6-dione, which undergoes spontaneous oxidation to form the blue pigment indigoidine.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Reverchon, S., Rouanet, C., Expert, D. and Nasser, W. Characterization of indigoidine biosynthetic genes in Erwinia chrysanthemi and role of this blue pigment in pathogenicity. J. Bacteriol. 184 (2002) 654-665. [PMID: 11790734]
2. Takahashi, H., Kumagai, T., Kitani, K., Mori, M., Matoba, Y. and Sugiyama, M. Cloning and characterization of a Streptomyces single module type non-ribosomal peptide synthetase catalyzing a blue pigment synthesis. J. Biol. Chem. 282 (2007) 9073-9081. [PMID: 17237222]
3. Walsh, C.T. and Wencewicz, T.A. Flavoenzymes: versatile catalysts in biosynthetic pathways. Nat. Prod. Rep. 30 (2013) 175-200. [PMID: 23051833]