1xqd
From Proteopedia
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Crystal structure of P450NOR complexed with 3-pyridinealdehyde adenine dinucleotide
Overview
Nitric oxide reductase cytochrome P450nor catalyzes an unusual reaction, direct electron transfer from NAD(P)H to bound heme. Here, we succeeded in determining the crystal structure of P450nor in a complex with an NADH analogue, nicotinic acid adenine dinucleotide, which provides conclusive evidence for the mechanism of the unprecedented electron transfer. Comparison of the structure with those of dinucleotide-free forms revealed a global conformational change accompanied by intriguing local movements caused by the binding of the pyridine nucleotide. Arg64 and Arg174 fix the pyrophosphate moiety upon the dinucleotide binding. Stereo-selective hydride transfer from NADH to NO-bound heme was suggested from the structure, the nicotinic acid ring being fixed near the heme by the conserved Thr residue in the I-helix and the upward-shifted propionate side-chain of the heme. A proton channel near the NADH channel is formed upon the dinucleotide binding, which should direct continuous transfer of the hydride and proton. A salt-bridge network (Glu71-Arg64-Asp88) was shown to be crucial for a high catalytic turnover.
About this Structure
1XQD is a Single protein structure of sequence from Fusarium oxysporum with and as ligands. Active as Nitric-oxide reductase, with EC number 1.7.99.7 Full crystallographic information is available from OCA.
Reference
Structural evidence for direct hydride transfer from NADH to cytochrome P450nor., Oshima R, Fushinobu S, Su F, Zhang L, Takaya N, Shoun H, J Mol Biol. 2004 Sep 3;342(1):207-17. PMID:15313618
Page seeded by OCA on Thu Feb 21 15:57:33 2008
