Single crystal structural and absorption spectral characterizations of nitric oxide synthase complexed with N(omega)-hydroxy-L-arginine and diatomic ligands.

ABSTRACT: The 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. Th

SUBMITTER: Doukov T 

PROVIDER: S-EPMC3740733 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature