Fig. 3.
Effect of actin truncation on its affinity for tropomyosin isoforms. Binding of smTM (A), TM2 (B), TM1b9a (C), and TM5a (D) to native F-actin (closed symbols) or F-actin−3 (open symbols) was assayed as described in Materials and methods. Conditions: 5 mM imidazole, 1 mM DTT, 150 mM NaCl, 2 mM MgCl2, with pH adjusted to 7.0, in the case of D) concentrations of NaCl and MgCl2 were respectively 30 and 0.5 mM. Data are from 3 to 5 independent experiments. Binding curves were drawn by fitting the experimental points to Hill equation (Eq. 1); (solid line) native F-actin; (dashed line) F-actin−3.