Ca2+-independent activity of nitric oxide synthase

Shiow Ju Lee, Kathy Beckingham, James T. Stull

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Ca2+-independent forms of nitric-oxide synthase have significant activity when the endogenous calmodulin subunit is Ca2+ free. Further activation is seen when Ca2+ is added. We have examined the activation of a Ca2+-independent nitric-oxide synthase variant and its two point mutants that are more dependent on Ca2+ for activation using mutant calmodulins containing non-functional Ca2+-binding sites. These studies provide evidence that the Ca2+-independent activity of these enzymes can be exerted through specific adapted interactions between the enzyme and the Ca2+-binding site 2 of calmodulin. Further, the results suggest that EGTA-sensitive metals other than Ca2+ complexed to calmodulin may be involved in maximal activation of these nitric-oxide synthase variants.

Original languageEnglish (US)
Pages (from-to)526-530
Number of pages5
JournalBiochemical and Biophysical Research Communications
Volume284
Issue number2
DOIs
StatePublished - Jan 1 2001

Keywords

  • Ca-independent activity
  • Calcium
  • Calmodulin
  • Chimera
  • Mutation
  • Nitric-oxide synthase

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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