Comparisons of Sepia officinalis myosin isoforms A, B1, B2, and C. A. Translated amino acid sequences of myosin heavy chain isoforms A, B1, and B2. Isoforms B1 and B2 contain a five amino acid deletion and four amino acid substitutions in surface loop 1 compared to isoform A. Isoform B1 differs from isoform B2 by three amino acids. B. Translated amino acid sequences of myosin heavy chain isoforms A and C. Isoform C contains a 12 amino acid extension compared to isoform A. Asterisks (*) denote identical amino acids, colons (:) denote well conserved amino acids, periods (.) denote somewhat conserved amino acids, and blank spaces denote no conservation.