cDNA cloning and thermodynamic properties of tropomyosin from walleye pollack Theragra chalcogramma fast skeletal muscle

Abstract

cDNA encoding tropomyosin was cloned from walleye pollack Theragra chalcogramma fast skeletal muscle. The predicted mass was 32 588 Da and isoelectric point, 4.55, assuming acetylation of the N-terminus. The full-length cDNA contained 1168 bp, comprising a 5′-untranslational region (97 bp), a 3′-untranslational region (219 bp) and an open reading frame of 855 bp encoding 284 amino acid residues. The deduced amino acid sequence showed considerably high homology in a range of 94.97% to those of other vertebrate α-type tropomyosins. In phylogenetic analysis, walleye pollack tropomyosin showed the closest relationship with the Atlantic salmon counterpart. By differential scanning calorimetry, pollack tropomyosin gave only one major endothermic peak at around 44°C. Circular dichroism spectra supported this denaturation profile of pollack tropomyosin.