35kDa fragment of h-caldesmon conserves two consensus sequences of the tropomyosin-binding domain in troponin T

Abstract Using a tropomyosin-coupled affinity column, we have demonstrated a direct association between the chymotryptic 35kDa fragment of h -caldesmon, which is located at the C-terminal of the parent molecule, and gizzard tropomyosin. We have subsequently determined the nucleotide sequence of cDNA clones encoding the 35kDa fragment from the cDNA library prepared from chick embryo gizzards, and have deduced the amino acid sequence. Calculating from the predicted sequence, the 35kDa fragment is composed of 306 amino acid residues. In agreement with the tropomyosin-binding ability, the 35kDa fragment conserves two consensus sequences of the tropomyosin-binding domain in troponin T. These results suggest that the 35kDa fragment of h -caldesmon, at least in part, has a common property to the striated muscle troponin T.