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Neuronal nitric-oxide synthase interaction with calmodulin-troponin C chimeras.

Publication ,  Journal Article
Gachhui, R; Abu-Soud, HM; Ghosha, DK; Presta, A; Blazing, MA; Mayer, B; George, SE; Stuehr, DJ
Published in: J Biol Chem
March 6, 1998

Calmodulin (CaM) binding activates neuronal nitric-oxide synthase (nNOS) catalytic functions and also up-regulates electron transfer into its flavin and heme centers. Here, we utilized seven tight binding CaM-troponin C chimeras, which variably activate nNOS NO synthesis to examine the relationship between CaM domain structure, activation of catalytic functions, and control of internal electron transfer at two points within nNOS. Chimeras that were singly substituted with troponin C domains 4, 3, 2, or 1 were increasingly unable to activate NO synthesis, but all caused some activation of cytochrome c reduction compared with CaM-free nNOS. The magnitude by which each chimera activated NO synthesis was approximately proportional to the rate of heme iron reduction supported by each chimera, which varied from 0% to approximately 80% compared with native CaM and remained coupled to NO synthesis in all cases. In contrast, chimera activation of cytochrome c reduction was not always associated with accelerated reduction of nNOS flavins, and certain chimeras activated cytochrome c reduction without triggering heme iron reduction. We conclude: 1) CaM effects on electron transfer at two points within nNOS can be functionally separated. 2) CaM controls NO synthesis by governing heme iron reduction, but enhances reductase activity by two mechanisms, only one of which is associated with an increased rate of flavin reduction.

Duke Scholars

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

March 6, 1998

Volume

273

Issue

10

Start / End Page

5451 / 5454

Location

United States

Related Subject Headings

  • Troponin C
  • Sequence Alignment
  • Recombinant Fusion Proteins
  • Rats
  • Nitric Oxide Synthase
  • Nitric Oxide
  • Neurons
  • NADP
  • Molecular Sequence Data
  • Kinetics
 

Citation

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Gachhui, R., Abu-Soud, H. M., Ghosha, D. K., Presta, A., Blazing, M. A., Mayer, B., … Stuehr, D. J. (1998). Neuronal nitric-oxide synthase interaction with calmodulin-troponin C chimeras. J Biol Chem, 273(10), 5451–5454. https://doi.org/10.1074/jbc.273.10.5451
Gachhui, R., H. M. Abu-Soud, D. K. Ghosha, A. Presta, M. A. Blazing, B. Mayer, S. E. George, and D. J. Stuehr. “Neuronal nitric-oxide synthase interaction with calmodulin-troponin C chimeras.J Biol Chem 273, no. 10 (March 6, 1998): 5451–54. https://doi.org/10.1074/jbc.273.10.5451.
Gachhui R, Abu-Soud HM, Ghosha DK, Presta A, Blazing MA, Mayer B, et al. Neuronal nitric-oxide synthase interaction with calmodulin-troponin C chimeras. J Biol Chem. 1998 Mar 6;273(10):5451–4.
Gachhui, R., et al. “Neuronal nitric-oxide synthase interaction with calmodulin-troponin C chimeras.J Biol Chem, vol. 273, no. 10, Mar. 1998, pp. 5451–54. Pubmed, doi:10.1074/jbc.273.10.5451.
Gachhui R, Abu-Soud HM, Ghosha DK, Presta A, Blazing MA, Mayer B, George SE, Stuehr DJ. Neuronal nitric-oxide synthase interaction with calmodulin-troponin C chimeras. J Biol Chem. 1998 Mar 6;273(10):5451–5454.

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

March 6, 1998

Volume

273

Issue

10

Start / End Page

5451 / 5454

Location

United States

Related Subject Headings

  • Troponin C
  • Sequence Alignment
  • Recombinant Fusion Proteins
  • Rats
  • Nitric Oxide Synthase
  • Nitric Oxide
  • Neurons
  • NADP
  • Molecular Sequence Data
  • Kinetics