Proton-magnetic-resonance studies on the interaction of rabbit skeletal-muscle troponin I with troponin C and actin.
1. The p.m.r. spectra of the larger CNBr-cleavage peptides of troponin I from rabbit fast-twitch skeletal muscle corresponded largely to those of fairly flexible solution structures. 2. On addition of troponin C to each of the CNBr-cleavage peptides in turn, perturbations of side chains were noted only for peptides CN5 (residues 1-21) and CN4 (residues 96-116). 3. In the presence of Ca2+, troponin C induced perturbations of the side chains of threonine-11, alanine, isoleucine and arginine residues of peptide CN5. 4. In the presence of Ca2+, troponin C induced perturbations of the side chains of phenylalanine, lysine and leucine residues of peptide CN4. 5. Irrespective of the presence or absence of Ca2+, specific interaction with actin was observed only with peptide CN4. In this case the side chains of arginine residues were perturbed. 6. It is concluded that actin interacts with the C-terminal region of peptide CN4, whereas troponin C interacts with the N-terminal region of peptide CN4 and with peptide CN5.
D000199:Actins / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology; D003488:Cyanogen Bromide; D009682:Magnetic Resonance Spectroscopy; D009124:Muscle Proteins / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011817:Rabbits; D014336:Troponin / Q000378:metabolism*; D019209:Troponin C; D019210:Troponin I
D000199:Actins; D009124:Muscle Proteins; D010446:Peptide Fragments; D014336:Troponin; D019209:Troponin C; D019210:Troponin I; D003488:Cyanogen Bromide; D002118:Calcium