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Ternary structure of neuronal nitric oxide synthase with NHA and CO boundTernary structure of neuronal nitric oxide synthase with NHA and CO bound
Structural highlights
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 PubMedThe X-ray structures of neuronal nitric oxide synthase (nNOS) with N(omega)-hydroxy-l-arginine (l-NHA) and CO (or NO) bound have been determined at 1.91-2.2 A resolution. Microspectrophotometric techniques confirmed reduced redox state and the status of diatomic ligand complexes during X-ray diffraction data collection. The structure of nNOS-NHA-NO, a close mimic to the dioxygen complex, provides a picture of the potential interactions between the heme-bound diatomic ligand, substrate l-NHA, and the surrounding protein and solvent structure environment. The OH group of l-NHA in the X-ray structures deviates from the plane of the guanidinium moiety substantially, indicating that the OH-bearing, protonated guanidine N(omega) nitrogen of l-NHA has substantial sp(3) hybridization character. This nitrogen geometry, different from that of the guanidinium N(omega) nitrogen of l-arginine, allows a hydrogen bond to be donated to the proximal oxygen of the heme-bound dioxygen complex, thus preventing cleavage of the O-O bond. Instead, it favors the stabilization of the ferric-hydroperoxy intermediate, Fe(3+)-OOH(-), which serves as the active oxidant in the conversion of l-NHA to NO and citrulline in the second reaction of the NOS. Single Crystal Structural and Absorption Spectral Characterizations of Nitric Oxide Synthase Complexed with N(omega)-Hydroxy-l-arginine and Diatomic Ligands (,).,Doukov T, Li H, Soltis M, Poulos TL Biochemistry. 2009 Oct 9. PMID:19791770[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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