Conformational change of troponin T induced by calcium binding to troponin C.
The skeletal muscle troponin complex, the troponin T subunit of which was labeled with 2-((4'-iodoacetamido)anilino)naphthalene-6-sulfonic acid, showed a fluorescence titration curve with a midpoint of around pCa 6.75. Addition of 2 mM MgCl2 had no effect on the fluorescence titration curve. Therefore, we conclude that Ca2+ binding to the low affinity Ca2+-binding sites of troponin C induces a conformational change of troponin T, but Ca2+ binding to the high affinity Ca2+-binding sites does not.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D009282:Naphthalenesulfonates; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D014336:Troponin / Q000378:metabolism*; D019209:Troponin C; D020107:Troponin T
D009282:Naphthalenesulfonates; D014336:Troponin; D019209:Troponin C; D020107:Troponin T; C011488:IAANS; D002118:Calcium