cDNA cloning and complete primary structures of myosin heavy chains from brushtooth lizardfish Saurida undosquamis and wanieso lizardfish S. wanieso fast skeletal muscles

The complete cDNA sequences encoding predominant types of myosin heavy chain (MYH) in the fast skeletal muscle were, determined for brushtooth lizardfish Saurida undosquamis and wanieso lizardfish S. wanieso, which are used as materials for preparing high-quality surimi-based products. The cDNA consisted of 5973 and 5987 bp, respectively, and both encompassed an open reading frame encoding a polypeptide of 1936 amino acid residues. Brushtooth and wanieso lizardfish MYH showed the amino acid, sequence identity of 92–93% to white croaker MYH, which was higher than that of 90% to walleye pollack MYH. The putative binding sites for ATP, actin, and regulatory and essential light chains in the subfragment-1 region of brushtooth lizardfish MYH exhibited a high identity with white croaker counterparts as well as the sequences of subfragment-2 and light meromyosin. In contrast, phylogenetic tree, constructed by the neighbor-joining method based on mitochondrial 16S rRNA gene, revealed that the two lizardfish species formed a cluster with walleye pollack, which was paraphyletic with white croaker. Therefore, a good reputation for lizardfish and white croaker to have a high thermal-gel forming ability seemed to be reflected by MYH rather than biolgoical similarity as revealed by the mitochondrial 16S rRNA gene.