Calmodulin Binding Site

The oxygenase and reductase domains are connected with a 20 amino acid calmodulin (CaM) binding region that is required in all NOS enzymes for the efficient transfer of the electrons from the reductase to the oxygenase domains. Electron transport is triggered by conformational changes induced by Ca2+/CaM binding, but this exact mechanism of activation is still not understood.


 This view shows in black the 20 amino acid peptide from Human Endothelial NOS. The Blue and Red are the N and C terminals respectively of Rat calmodulin that bind and encompass the CaM binding peptide. They are shown in space filling view.

The eNOS peptide binds CaM in a classical antiparallel orientation with is shown in this view. 


EMBO J. 2003 Feb 17;22(4):766-75.
Structural basis for endothelial nitric oxide synthase binding to calmodulin.
Aoyagi M1, Arvai AS, Tainer JA, Getzoff ED. PubMed

1NIW(PDB)

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