title: Amino acid sequence of rabbit cardiac troponin T.
abstract: The complete amino acid sequence of the major isoform of rabbit cardiac troponin T was determined by the application of manual and automated Edman degradation procedures to fragments generated by suitable chemical or proteolytic cleavages. The protein has a polypeptide chain length of 276 amino acid residues, a Mr of 32,881, is negatively charged at neutral pH, and must be encoded by a different structural gene than rabbit skeletal troponin T. A more basic isoform differs in the NH2-terminal region by the replacement of 7 glutamic acid residues by neutral amino acids. Comparison of the sequence with that of rabbit skeletal troponin T shows close homology in those structural regions (residues 47-151 and 170-236 of rabbit skeletal troponin T) previously implicated in interactions with tropomyosin, troponin I and troponin C and predicts similar secondary structural features. In addition, the NH2- (16 residues) and COOH-terminal (10 residues) segments are homologous. In the cardiac protein, the regions of residues 17-46, 152-169, and 237-249 (rabbit skeletal troponin T numbering scheme) show little similarity with the skeletal protein and include multiple amino acid differences as well as insertions and/or deletions. Within these nonhomologous segments, however, there are regions of high similarity or identity with the amino acid sequence of chicken cardiac troponin T deduced from DNA sequencing (Cooper, T.A., and Ordahl, C.P. (1985) J. Biol. Chem. 260, 11140-11148). These include residues 36-46, 152-161, and 237-242 and may represent regions of functional importance for cardiac troponin T as compared with the skeletal protein.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D005796:Genes; D009132:Muscles / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D009928:Organ Specificity; D010446:Peptide Fragments / Q000032:analysis; D011817:Rabbits; D013045:Species Specificity; D014336:Troponin / Q000235:genetics / Q000302:isolation & purification; D020107:Troponin T; D014357:Trypsin
chemical_list: D010446:Peptide Fragments; D014336:Troponin; D020107:Troponin T; D014357:Trypsin