The sites on calmodulin cross-linked to myosin light chain kinase and troponin I with water-soluble carbodiimide.
To elucidate the interaction of calmodulin with calmodulin binding proteins, we studied the location of the interaction sites on calmodulin by using a chemical cross-linking reagent. Calmodulin prepared from wheat germ was cross-linked to myosin light chain kinase and troponin-I with 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide. The cross-linked products were cleaved partially with cyanogen bromide and cross-linked sites were determined by peptide mapping analysis using SDS-urea polyacrylamide gel electrophoresis. Peptides which contain the cross-linked site were displaced from their position because of the attached fragments of myosin light chain kinase or troponin I. The peptide of calmodulin from the N-terminal to Met-73 in the cross-linked product with myosin light chain kinase had the same mobility as that of uncross-linked calmodulin on the map though the amount of the peptide was decreased in the cross-linked product. The peptide from the N-terminal to Met-110 in the cross-linked product was displaced from its position. Similar change in the mobility of the calmodulin peptides was also observed in the cross-linked products with troponin I. It was concluded, therefore, that at least one cross-linked site for myosin light chain kinase and one for troponin I were located between Met-73 and Met-110 of the wheat germ calmodulin.
Yamamoto
K
K
Faculty of Liberal Arts, University of the Air, Chiba.
Sekine
T
T
Sutoh
K
K
D001665:Binding Sites; D002147:Calmodulin / Q000378:metabolism*; D002234:Carbodiimides / Q000494:pharmacology*; D003432:Cross-Linking Reagents; D003488:Cyanogen Bromide; D004591:Electrophoresis, Polyacrylamide Gel; D007202:Indicators and Reagents; D008301:Maleimides; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism*; D010449:Peptide Mapping; D012995:Solubility; D014336:Troponin / Q000378:metabolism*; D019210:Troponin I
D002147:Calmodulin; D002234:Carbodiimides; D003432:Cross-Linking Reagents; D007202:Indicators and Reagents; D008301:Maleimides; D014336:Troponin; D019210:Troponin I; C019347:N-(7-dimethylamino-4-methylcoumarinyl)maleimide; D009219:Myosin-Light-Chain Kinase; D003488:Cyanogen Bromide