Threonine-77 Is a Determinant of the Low-Temperature Conditioning of the Most Abundant Isoform of Tropomyosin in Atlantic Salmon.

The Atlantic salmon survives below 10 °C. The main skeletal muscle is composed of a single isoform of tropomyosin (classified as Tpm1 α-fast) that is >92% identical to the mammalian homologue. How salmon Tpm1 maintains flexibility is investigated by reversing the only full charge substitution; threonine-77(g) in salmon and lysine in other vertebrates.

Vertebrate slow skeletal muscle actin - conservation, distribution and conformational flexibility.

The existence of a unique sarcomeric actin is demonstrated in teleosts that possess substantial amounts of slow skeletal muscle in the trunk. The slow skeletal isotype is conserved. There is one amino acid substitution between Atlantic herring slow skeletal actin and the equivalent in salmonids.