FIGURE 6.

Effect of Tn exchange on skinned cardiac muscle force generation. A, the Ca²⁺-dependent force generation for skinned trabeculae without Tn exchange (endogenous, □) and without Tn exchange but going through the same exchange protocol (mock exchange, ★) and for skinned trabeculae exchanged with control Tn_IAANS^T53C (□). Data traces were individually normalized. B, a Western blot for cardiac TnI demonstrating the presence of experimental human TnI in representative single trabecula from force experiments. Both wild-type and human TnI-(1–192) migrate faster than endogenous rat TnI, allowing for the quantification of human Tn exchanged into trabeculae from functional measurements. Human TnI (1–192), recombinant, purified human TnI-(1–192) fragment; Rat and Human TnI, mixed recombinant wild-type rat (50%) and human purified TnI (50%).