Reductase Domain of NOS

The C-terminal reductase domain contains binding sites for FMN, FAD, and NADPH. The NOS oxygenase domain accepts electrons from NOSred to catalyze the sequential monooxygenation of L-arginine into N-hydroxyarginine, then citrulline and NO. NOSred belongs to a large protein family that includes NADPH-dependent cytochrome P450 reductase (CYPOR), sulfite reductase flavoprotein and novel reductase 1. These reductases share a conserved organization of flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), and nicotinamide adenine dinucleotide phosphate (NADPH)-binding domains.


 This view shows both domains of Rat Neuronal NOXred. The bound FMN is shown in yellow, FAD in dark gray, and NAP in orange.

This shows a close up of one domain of the reductase. The electrons move from NADPH to FAD to FMN (orange to yellow) and eventually get to heme in the oxygenase domain.

This view shows the domains in one monomer: The FMN binding domain, the connecting domain,flexible hinge,β-finger,FAD binding domain,and NADPH binding domain


2004 Sep 3;279(36):37918-27. Epub 2004 Jun 17.
Structural basis for isozyme-specific regulation of electron transfer in nitric-oxide synthase.
Garcin ED1, Bruns CM, Lloyd SJ, Hosfield DJ, Tiso M, Gachhui R, Stuehr DJ, Tainer JA, Getzoff ED. PubMed

1TLL(PDB)

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