(A) Atomic model of the cardiac actomyosin complex shows structural elements of cardiac myosin involved in interactions with actin and tropomyosin: CM loop (blue ribbons), loop 2 (red ribbons), loop 4 (yellow ribbons), HLH motif (cyan ribbons), and loop 3 (brown ribbons). Actin atoms are tan, tropomyosin is black, while myosin motor domain is plum. Myosin residues involved in interactions with actin are in magenta while myosin residues involved in intra-myosin contacts are in green. (B-H) Detailed interfaces between myosin tropomyosin and actin are shown for CM loop (B and C), loop 2 (D), loop 4 (E), HLH motif (F and G), and loop 3(H).