Raggi A, Grand R J, Moir A J, Perry S V
Istituto di Chimica Biologica Università di Pisa, Italy.
Biochim Biophys Acta. 1989 Jul 27;997(1-2):135-43. doi: 10.1016/0167-4838(89)90145-3.
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.
已确定兔和牛心肌肌钙蛋白T中与原肌球蛋白、肌钙蛋白C和肌钙蛋白I结合相关的区域。已定位到原肌球蛋白的两个接触位点，位于肌钙蛋白T的92 - 178位残基和180 - 284位残基之间。已在心肌肌钙蛋白T的1 - 68位残基之间确定了一个心肌特异性的肌钙蛋白I结合位点，该位点位于该蛋白质的一个区域内，此前已证明该区域由一系列以组织特异性和发育调控方式表达的外显子编码。肌钙蛋白C的结合位点位于心肌肌钙蛋白T的180 - 284位残基之间。从新鲜牛心脏中分离出的心肌肌钙蛋白T，每摩尔含有0.21±0.11摩尔磷酸盐；与磷酸化酶激酶孵育可使磷酸盐含量增加到约每摩尔1摩尔磷酸盐。一个磷酸化位点被确定为丝氨酸 - 1；第二个磷酸化位点位于肽CB3（93 - 178位残基）内，初步确定为丝氨酸 - 176。向心肌肌钙蛋白T中添加肌钙蛋白C不会抑制磷酸化酶b激酶催化的该蛋白质的磷酸化。
