1xqd
From Proteopedia
Crystal structure of P450NOR complexed with 3-pyridinealdehyde adenine dinucleotide
Structural highlights
Function[NOR_FUSOX] Nitric oxide reductase which is involved in a dissimilatory reduction of nitrite. Acts as a nitric oxide reductase. Is able to reduce nitrate and nitrite to a gaseous form of N(2)O when oxygen supply is limited or discontinued. May function as a detoxification mechanism.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedNitric 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. 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[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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