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 language | English (US) |
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Pages (from-to) | 526-530 |
Number of pages | 5 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 284 |
Issue number | 2 |
DOIs | |
State | Published - 2001 |
Keywords
- Ca-independent activity
- Calcium
- Calmodulin
- Chimera
- Mutation
- Nitric-oxide synthase
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology