Structure-function relationships in cardiac troponin T.
Regions of rabbit and bovine cardiac troponin T that are involved in binding tropomyosin, troponin C and troponin I have been identified. Two sites of contact for tropomyosin have been located, situated between residues 92-178 and 180-284 of troponin T. A cardiac-specific binding site for troponin I has been identified between residues 1-68 of cardiac troponin T, within a region of the protein that has previously been shown to be encoded by a series of exons that are expressed in a tissue-specific and developmentally regulated manner. The binding site for troponin C is located between residues 180-284 of cardiac troponin T. When isolated from fresh bovine hearts, cardiac troponin T contained 0.21 +/- 0.11 mol phosphate per mol; incubation with phosphorylase kinase increased the phosphate content to approx. 1 mol phosphate per mol. One site of phosphorylation was identified as serine-1; a second site of phosphorylation was located within peptide CB3 (residues 93-178) and has been tentatively identified as serine-176. Addition of troponin C to cardiac troponin T does not inhibit the phosphorylation of this latter protein that is catalysed by phosphorylase b kinase.
Raggi
A
A
Istituto di Chimica Biologica Università di Pisa, Italy.
Grand
R J
RJ
Moir
A J
AJ
Perry
S V
SV
D000818:Animals; D003488:Cyanogen Bromide; D004591:Electrophoresis, Polyacrylamide Gel; D009206:Myocardium / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011817:Rabbits; D013329:Structure-Activity Relationship; D014335:Tropomyosin / Q000378:metabolism; D014336:Troponin / Q000378:metabolism*; D019209:Troponin C; D019210:Troponin I; D020107:Troponin T; D014357:Trypsin; D014783:Viscosity
D014335:Tropomyosin; D014336:Troponin; D019209:Troponin C; D019210:Troponin I; D020107:Troponin T; D014357:Trypsin; D003488:Cyanogen Bromide