title: Differential calmodulin-modulatory and electron transfer properties of neuronal nitric oxide synthase mu compared to the alpha variant.
abstract: Neuronal nitric oxide synthase μ (nNOSμ) contains 34 additional residues in an autoregulatory element compared to nNOSα. Cytochrome c and flavin reductions in the absence of calmodulin (CaM) were faster in nNOSμ than nNOSα, while rates in the presence of CaM were smaller. The magnitude of stimulation by CaM is thus notably lower in nNOSμ. No difference in NO production was observed, while electron transfer between the FMN and heme moieties and formation of an inhibitory ferrous-nitrosyl complex were slower in nNOSμ. Thus, the insert affects electron transfer rates, modulation of electron flow by CaM, and heme-nitrosyl complex formation.
authors.affiliation: Department of Biochemistry, University of Texas Health Science Center in San Antonio, San Antonio, TX 78229, USA.
authors.forename: Satya P
authors.initials: SP
authors.lastname: Panda
authors.forename: Wenbing
authors.initials: W
authors.lastname: Li
authors.forename: Priya
authors.initials: P
authors.lastname: Venkatakrishnan
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Astashkin
authors.forename: Bettie Sue S
authors.initials: BS
authors.lastname: Masters
authors.forename: Changjian
authors.initials: C
authors.lastname: Feng
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Roman
mesh_terms: D000595:Amino Acid Sequence / Q000502:physiology; D000818:Animals; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism*; D045304:Cytochromes c / Q000378:metabolism; D004579:Electron Transport / Q000502:physiology; D005486:Flavin Mononucleotide / Q000378:metabolism; D006418:Heme / Q000737:chemistry / Q000378:metabolism; D007527:Isoenzymes / Q000737:chemistry / Q000502:physiology; D009569:Nitric Oxide / Q000096:biosynthesis; D052248:Nitric Oxide Synthase Type I / Q000737:chemistry / Q000502:physiology*; D011485:Protein Binding; D051381:Rats
chemical_list: D002147:Calmodulin; D007527:Isoenzymes; D009569:Nitric Oxide; D006418:Heme; D005486:Flavin Mononucleotide; D045304:Cytochromes c; D052248:Nitric Oxide Synthase Type I
keywords: AR; C-terminal tail region; CT; CaM; Calmodulin; Electron transfer; Flavoproteins; H(4)B; Heme; IET; NO; NOS; Neuronal nitric oxide synthase; Reductase; autoregulatory region; calmodulin; interdomain electron transfer; l-Arg; l-arginine; nNOS; neuronal NOS; nitric oxide; nitric oxide synthase; tetrahydrobiopterin