Mechano-chemical effects of Ca2+ in cross-linked troponin-C films

AbstractChanges in troponin C (TnC) conformation upon Ca2+ binding forms the basis for regulatory and structural functions of TnC molecules. In the present study, Ca2+-induced conformational changes in TnC were observed by mechanical measurements. TnC films were prepared by drying or electrospraying TnC solutions, cross-linked with glutaraldehyde, and isometric tension and stiffness measured as a function of pCa. An increase in Ca2+ from a pCa of 9 to 4 induced large-scale mechanical changes in the TnC films causing several percent shrinkage of the unloaded films. This shrinkage could be partially assigned to Ca2+ binding to the Ca2+/Mg2+ sites of TnC