Accepted name: 8-demethyl-8-aminoriboflavin-5′-phosphate synthase
Reaction: L-glutamate + FMN + O2 + H2O + 3 acceptor = 2-oxoglutarate + 8-amino-8-demethylriboflavin 5′-phosphate + CO2 + 3 reduced acceptor (overall reaction)
(1a) FMN + O2 = 8-demethyl-8-formylriboflavin 5′-phosphate + H2O
(1b) 8-demethyl-8-formylriboflavin 5′-phosphate + H2O + acceptor = 8-carboxy-8-demethylriboflavin 5′-phosphate + reduced acceptor
(1c) L-glutamate + 8-carboxy-8-demethylriboflavin 5′-phosphate + H2O + 2 acceptor = 2-oxoglutarate + 8-amino-8-demethylriboflavin 5′-phosphate + CO2 + 2 reduced acceptor
Glossary: roseoflavin = 8-demethyl-8-(dimethylamino)riboflavin
Other name(s): rosB (gene name)
Systematic name: L-glutamate:FMN aminotransferase (oxidizing, decarboxylating)
Comments: The enzyme, characterized from the bacterium Streptomyces davawensis, has the activities of an oxidoreductase, a decarboxylase, and an aminotransferase. Its combined actions result in the replacement of a methyl substituent of one of the aromatic rings of FMN by an amino group, a step in the biosynthetic pathway of roseoflavin. The reaction requires thiamine for completion.
1.  Schwarz, J., Konjik, V., Jankowitsch, F., Sandhoff, R. and Mack, M. Identification of the key enzyme of roseoflavin biosynthesis. Angew. Chem. Int. Ed. Engl. 55 (2016) 6103–6106. [PMID: 27062037]
2.  Jhulki, I., Chanani, P.K., Abdelwahed, S.H. and Begley, T.P. A remarkable oxidative cascade that replaces the riboflavin C8 methyl with an amino group during roseoflavin biosynthesis. J. Am. Chem. Soc. 138 (2016) 8324–8327. [PMID: 27331868]
3.  Konjik, V., Brunle, S., Demmer, U., Vanselow, A., Sandhoff, R., Ermler, U. and Mack, M. The crystal structure of RosB: insights into the reaction mechanism of the first member of a family of flavodoxin-like enzymes. Angew. Chem. Int. Ed. Engl. 56 (2017) 1146–1151. [PMID: 27981706]
[EC created 2018]

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