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Calmodulin‐induced structural changes in endothelial nitric oxide synthase
Author(s) -
Persechini Anthony,
Tran Quang-Kim,
Black D.J.,
Gogol Edward P.
Publication year - 2013
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2012.12.012
Subject(s) - calmodulin , docking (animal) , chemistry , oxygenase , reductase , nitric oxide synthase , binding site , biophysics , stereochemistry , biochemistry , enzyme , biology , medicine , nursing
We have derived structures of intact calmodulin (CaM)‐free and CaM‐bound endothelial nitric oxide synthase (eNOS) by reconstruction from cryo‐electron micrographs. The CaM‐free reconstruction is well fitted by the oxygenase domain dimer, but the reductase domains are not visible, suggesting they are mobile and thus delocalized. Additional protein is visible in the CaM‐bound reconstruction, concentrated in volumes near two basic patches on each oxygenase domain. One of these corresponds with a presumptive docking site for the reductase domain FMN‐binding module. The other is proposed to correspond with a docking site for CaM. A model is suggested in which CaM binding and docking position the reductase domains near the oxygenase domains and promote docking of the FMN‐binding modules required for electron transfer.