Nucleotide binding to creatine kinase: an isothermal titration microcalorimetry study

FEBS Letters

Forstner, Michael¹  Wallimann, Theo¹  Berger, Christine² 

[1] Institute of Cell Biology, Swiss Federal Institute of Technology Zürich, ETH Hönggerberg, CH-8093 Zürich, Switzerland;Institute of Biochemistry, University of Zürich-Irchel, CH-8057 Zürich, Switzerland

关键词: Calorimetry;    Creatine kinase;    Domain movement;    Thermodynamic cycle;   

DOI  :  10.1016/S0014-5793(99)01431-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We investigated the binding of ATP in the presence and absence of Mg²⁺ to dimeric muscle creatine kinase (CK) by isothermal titration microcalorimetry as a function of pH and temperature. The thermodynamic parameters for these events show that (1) binding of nucleotide to the CK active site does not involve proton exchange with the buffer and (2) the active sites are the only nucleotide binding sites on CK. Interdependence of the active sites in the dimer could not be demonstrated. As CK undergoes major structural changes upon Mg-nucleotide binding, a thermodynamic cycle was employed to calculate the contributions of domain movements to the observed enthalpies.

【 授权许可】

Unknown