Cryo-EM structures of skeletal muscle myosin II [24] and myosin V [27] bound to F-actin show direct electrostatic interactions between loop 4 and actin, though loop 4 of myosin V localizes closer towards the cardiomyopathy loop where it forms an intramolecular hydrogen bond. The gene discussed is MYO5A; the disease is cardiomyopathy.