Figure 6.

Troponin T N-terminal fragment does not affect the M8R tropomyosin. A, the diminished effect of troponin T N-terminal fragment (TnT) on the speed of actin–tropomyosin (Tpm) filaments bearing the M8R mutation (filled bars) versus WT (open bars). These values are from the in vitro motility assay, where tropomyosin and troponin T fragment were added in excess of 0.6 μm. B, analysis of multiple concentrations of troponin T binding to excess tropomyosin (10 μm for M8R, filled circles; 5 μm for WT, open circles) shows that the troponin T fragment binds M8R tropomyosin decorated actin filaments with greatly reduced affinity.