Identification of a specific amino acid cluster in the calmodulin-binding domain of the neuronal nitric oxide synthase.
The calmodulin (CaM) binding domain of rat neuronal nitric oxide synthase (nNOS) was analyzed using 3 synthetic peptides corresponding to different regions of the middle portion of the enzyme. One corresponding to nNOS 732-754 gave complete inhibition of NOS enzyme activity with an IC50 of about 1 microM. Kinetic analysis indicated that the inhibition was not competitive with respect to L-arginine and the peptide produced a Ca2+ dependent, electrophoretic mobility shift of CaM on 1 M urea gels. A specific hydrophobic/basic amino acid cluster in the rat nNOS sequence, Lys732 Lys Leu, that was critical for its CaM binding was also identified in this study.
Watanabe
Y
Y
Department of Pharmacology, Nagoya University School of Medicine, Showa-ku, Japan.
Hu
Y
Y
Hidaka
H
H
D000595:Amino Acid Sequence; D001665:Binding Sites; D002147:Calmodulin / Q000378:metabolism*; D004586:Electrophoresis / Q000379:methods; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid
D002147:Calmodulin; D010446:Peptide Fragments; D019001:Nitric Oxide Synthase