Protein-protein interaction sites in the calcium modulated skeletal muscle troponin complex

The sequence domains that contribute to the surfaces of contact between Troponin-C and the other regulatory protein subunits of skeletal muscle troponin are proposed on the basis of data obtained by proton magnetic resonance and other physicochemical studies on the interaction with Troponin-I of both Troponin-C and its peptide fragments. Marked sequence homology in Troponin-C from various species is found for the residues involved in subunit linkage. The role of the recognition sites is discussed.