MYH7 and cardiomyopathy: A similar variable cluster of three residues was found in Helix L for the two cardiac myosin isoforms, residues 347–349 (NSM in β and AGV in α) (18), and lies between two highly conserved lysines at 346 and 351 of which Lys-351 in MyHC-β also is a human cardiomyopathy site.