Actin-binding site of pig cardiac myosin

An actin-binding site is also present in the tryptic 20 kDa peptide fragment of the subfragment-1 heavy chain of pig cardiac myosin. As previously reported for skeletal myosin (Katoh, T., Katoh, H., and Morita, F. (1985) J. Biol. Chem. 260, 6723-6727), the site was further narrowed down to the 10 kDa peptide containing the reactive SH1 and SH2 groups. Thus it appears that the actin-binding site around the two thiols found in skeletal myosin is common to different types of myosin.