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Solution Structures of CaM‐iNOS and CaM‐eNOS peptide complexes: Effects of a phosphomimetic CaM mutation
Author(s) -
Piazza Michael,
Dieckmann Thorsten,
Guillemette J Guy
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.757.1
Subject(s) - enos , calmodulin , nitric oxide synthase , endothelial nos , nitric oxide synthase type iii , peptide , nitric oxide , chemistry , phosphorylation , enzyme , mutant , atp synthase , biochemistry , endothelial nitric oxide synthase , microbiology and biotechnology , biophysics , biology , gene , organic chemistry
NMR spectroscopy is an efficient method for studying the dynamics and structures of protein‐protein and protein‐peptide complexes. Nitric oxide synthase (NOS) functions in key physiological processes. Calmodulin (CaM), is required to fully activate the enzyme. Studies have shown CaM to act like a switch that causes a conformational change in NOS through a process that is thought to be highly dynamic. To investigate the dynamic properties of CaM‐NOS interactions, we determined the solution structure of CaM bound to the inducible NOS (iNOS) and endothelial NOS (eNOS) CaM‐binding region peptides. In addition, we investigated the structural and functional effects of CaM phopsphorylation on NOS using a phosphomimetic Y99E CaM. Our results show that Y99E CaM significantly reduces maximal synthase activity of eNOS by 40% while having little effect on nNOS and iNOS activity. A comparative NMR study between Y99E CaM and wt‐CaM bound to the eNOS peptide was performed. This investigation provides important insights into the effects that CaM phosphorylation has upon the binding and activation of the NOS enzymes. This work was funded by the NSERC of Canada.