Cloning and expression of salmon cardiac troponin C: titration of the low-affinity Ca2+-binding site using a tryptophan mutant

The influence of the calcium (Ca2+)-binding site of troponin C (cTnC) in striated muscle myofibrils on muscle contraction was investigated. Cloning and sequencing of cTnC isolated from cold-water salmonid, Onchorhynchus mykiss, revealed that the Ca2+-binding site is involved in the regulation of contraction by influencing the interaction of cTnC with other troponin proteins in vertebrate muscle.