2g6o

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spinqualitylabelsall models 2g6o, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Structure of bovine eNOS heme domain (BH4-free) complexed with CO

Overview

Crystal structures are reported for the endothelial nitric oxide synthase, (eNOS)-arginine-CO ternary complex as well as the neuronal nitric oxide, synthase (nNOS) heme domain complexed with L: -arginine and diatomic, ligands, CO or NO, in the presence of the native cofactor, tetrahydrobiopterin, or its oxidized analogs, dihydrobiopterin and, 4-aminobiopterin. The nature of the biopterin has no influence on the, diatomic ligand binding. The binding geometries of diatomic ligands to, nitric oxide synthase (NOS) follow the {MXY}(n) formalism developed from, the inorganic diatomic-metal complexes. The structures reveal some subtle, structural differences between eNOS and nNOS when CO is bound to the heme, which correlate well with the differences in CO stretching frequencies, observed by resonance Raman techniques. The detailed hydrogen-bonding, geometries depicted in the active site of nNOS structures indicate that it, is the ordered active-site water molecule rather than the substrate itself, that would most likely serve as a direct proton donor to the diatomic, ligands (CO, NO, as well as O(2)) bound to the heme. This has important, implications for the oxygen activation mechanism critical to NOS, catalysis.

About this Structure

2G6O is a Single protein structure of sequence from Bos taurus with ACT, CAC, ZN, HEM, ARG, CMO and GOL as ligands. Active as Nitric-oxide synthase, with EC number 1.14.13.39 Full crystallographic information is available from OCA.

Reference

Structural studies of constitutive nitric oxide synthases with diatomic ligands bound., Li H, Igarashi J, Jamal J, Yang W, Poulos TL, J Biol Inorg Chem. 2006 Sep;11(6):753-68. Epub 2006 Jun 28. PMID:16804678

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