Table 1.

Ca²⁺ dependence of isometric force (mean ±s.e.m.)

	C helix; TnC-BR55-62 (n= 5)	E helix; TnC-BR95-102 (n= 5)	Wild-type TnC (n= 4)
Before TnC reconstitution
EC50 (μm)	2.53 ± 0.21	1.82 ± 0.33	1.29 ± 0.25
nH	3.51 ± 0.48	3.59 ± 0.15	3.57 ± 0.45
After TnC reconstitution
Maximum force	0.82 ± 0.03	0.84 ± 0.02	0.82 ± 0.01
EC50 (μm)	5.40 ± 0.57	3.17 ± 0.49	1.54 ± 0.30
nH	3.10 ± 0.24	2.92 ± 0.25	3.13 ± 0.43

EC₅₀ and n_H are fitted parameters of the Hill equation (see Methods). Maximum Ca²⁺-saturated force was measured after TnC exchange as a fraction of that in the same trabeculae before exchange.