Fig. 3. Amino acid sequences of representative calpains. Amino acid sequences of representative members of the calpain superfamily are aligned to show the highest identity for domains IIa (A), IIb (B), III (C), and IV (D). Numbers, secondary structures, and intron insertion positions at the top of each alignment correspond to those of human m-calpain. Asterisks and amino acid residue substitutions at the bottom of each alignment indicate the pathogenic p94 gene mutation causing limb-girdle muscular dystrophy type 2A (14). Residues conserved in all calpains compared are shown in inverted yellow; residues conserved in more than half of the calpains compared are shown in white. Gray inverted letters represent amino acid residues similar to those of the conserved residue.