Cloning and sequencing of a cDNA for Akazara scallop troponin T.

A cDNA clone encoding troponin T of Akazara scallop (Chlamys nipponensis akazara) striated adductor muscle has been isolated and sequenced. The complete sequence deduced consists of 314 amino acid residues with a molecular weight of 37,206. Akazara scallop troponin T contains 55 amino acid residues more and 82 residues fewer than rabbit skeletal muscle troponin T and Drosophila melanogaster troponin T, respectively, showing almost the lowest sequence homology with rabbit troponin T (26%) but the highest homology with Drosophila troponin T (33%). Further, high sequence homology was seen in the functional regions: residues 33-120 and 174-227, corresponding respectively to residues 71-158 and 197-250 of rabbit troponin T (tropomyosin-binding regions); and residues 200-204, corresponding to 223 227 of rabbit troponin T (troponin I-binding region). In residues 1-70 (tropomyosin-binding region), however, only six residues are identical with rabbit troponin T.