824068.fig.004
Figure 4: Comparison of normalized pCa-tension relationships in detergent-skinned fibers reconstituted with cTnCWT, c T n C L 2 9 Q , or c T n C G 1 5 9 D . Isometric steady-state tensions elicited by each fiber in various pCa solutions were normalized with its respective value in pCa 4.3 solution. The normalized tensions were plotted against pCa to construct the pCa-tension relationship. The Hill equation was fitted to the normalized pCa-tension relationships to estimate myofilament C a 2 + sensitivity ( p C a 5 0 ) and the Hill coefficient ( 𝑛 H ). 𝑝 𝐶 𝑎 5 0 and 𝑛 H values are shown in Figures 5(a) and 5(b), respectively. The curves presented here are Hill fits to pCa-tension relationships in cTnCWT (○), c T n C L 2 9 Q (□), and c T n C G 1 5 9 D (∆) fibers, respectively. Values are expressed as mean ± SEM. Number of fibers tested in each group is as follows: c T n C W T , 𝑛 = 1 5 ; c T n C L 2 9 Q , 𝑛 = 1 0 ; c T n C G 1 5 9 D , 𝑛 = 1 4 .