Reaction: aurachin C + NAD(P)H + H+ + O2 = 4-hydroxy-2-methyl-3-oxo-4-[(2E,6E)-farnesyl]-3,4-dihydroquinoline 1-oxide + NAD(P)+ + H2O (overall reaction)
(1a) aurachin C + NAD(P)H + H+ + O2 = 2-hydroxy-1a-methyl-7a-[(2E,6E)-farnesyl]-1a,2-dihydrooxireno[2,3-b]quinolin-7(7aH)-one + NAD(P)+ + H2O
(1b) 2-hydroxy-1a-methyl-7a-[(2E,6E)-farnesyl]-1a,2-dihydrooxireno[2,3-b]quinolin-7(7aH)-one = 4-hydroxy-2-methyl-3-oxo-4-[(2E,6E)-farnesyl]-3,4-dihydroquinoline 1-oxide
For diagram of reaction click here and for mechanism click here.
Glossary: aurachin C = 1-hydroxy-2-methyl-3-[(2E,6E)-farnesyl]-4(1H)-quinolinone
2-hydroxy-1a-methyl-7a-[(2E,6E)-farnesyl]-1a,2-dihydrooxireno[2,3-b]quinolin-7(7aH)-one = 2-hydroxy-1a-methyl-7a-((2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl)-1a,2-dihydrooxireno[2,3-b]quinolin-7(7aH)-one
4-hydroxy-2-methyl-3-oxo-4-[(2E,6E)-farnesyl]-3,4-dihydroquinoline 1-oxide = 4-hydroxy-2-methyl-4-[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]quinolin-3(4H)-one 1-oxide
aurachin B = 2-methyl-4-[(2E,6E)-farnesyl]-3-quinolinol 1-oxide
Other name(s): auaG (gene name); aurachin C monooxygenase
Systematic name: aurachin C:NAD(P)H:oxygen oxidoreductase (4-hydroxy-2-methyl-3-oxo-4-farnesyl-3,4-dihydroquinoline-1-oxide-forming)
Comments: The aurachin C monooxygenase from the bacterium Stigmatella aurantiaca accepts both NADH and NADPH as cofactor, but has a preference for NADH. It catalyses the initial steps in the conversion of aurachin C to aurachin B. The FAD-dependent monooxygenase catalyses the epoxidation of the C2-C3 double bond of aurachin C, which is followed by a semipinacol rearrangement, causing migration of the farnesyl group from C3 to C4.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Katsuyama, Y., Harmrolfs, K., Pistorius, D., Li, Y. and Muller, R. A semipinacol rearrangement directed by an enzymatic system featuring dual-function FAD-dependent monooxygenase. Angew Chem Int Ed Engl 51 (2012) 9437-9440. [PMID: 22907798]