Dynamic secondary structural changes in Ca2+-saturated calmodulin upon interaction with the antagonist, W-7

► 2D FTIR establish Ca2+/CaM conformational changes induced by W-7. ► A stepwise process of structural changes of the complex occurred in initial 125 s. ► α-helix of Ca2+/CaM also changed in the complex with W-7. ► Ca2+/CaM resulted in a rigidification of the complex interact with W-7.