Activation of regulated actin by SH1-modified myosin subfragment 1

In vitro motility assays were used in studying the interaction of SH1-modified myosin heads with regulated and unregulated actin. Results reveal that the in vitro sliding of regulated actin is activated by SH1 modified myosin heads. Modified SH1 disrupts the motor function of myosin heads and converts them as effective activators of regulated actin. This supports the order of the SH1 group as an attachment site for myosin cross-bridge probes in the force-generating states.