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Publication Abstract from PubMed

Nitric oxide is generated under normal and pathophysiological conditions by three distinct isoforms of nitric oxide synthase (NOS). A small-molecule inhibitor of NOS (3-Br-7-nitroindazole, 7-NIBr) is profoundly neuroprotective in mouse models of stroke and Parkinson's disease. We report the crystal structure of the catalytic heme domain of endothelial NOS complexed with 7-NIBr at 1.65 A resolution. Critical to the binding of 7-NIBr at the substrate site is the adoption by eNOS of an altered conformation, in which a key glutamate residue swings out toward one of the heme propionate groups. Perturbation of the heme propionate ensues and eliminates the cofactor tetrahydrobiopterin-heme interaction. We also present three crystal structures that reveal how alterations at the substrate site facilitate 7-NIBr and structurally dissimilar ligands to occupy the cofactor site.

Crystal structure of nitric oxide synthase bound to nitro indazole reveals a novel inactivation mechanism.,Raman CS, Li H, Martasek P, Southan G, Masters BS, Poulos TL Biochemistry. 2001 Nov 13;40(45):13448-55. PMID:11695891^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.