Structural changes of creatine kinase upon substrate binding

Biophys J. 1998 Aug;75(2):1016-23. doi: 10.1016/S0006-3495(98)77590-3.

Abstract

Small-angle x-ray scattering was used to investigate structural changes upon binding of individual substrates or a transition state analog complex (TSAC; Mg-ADP, creatine, and KNO3) to creatine kinase (CK) isoenzymes (dimeric muscle-type (M)-CK and octameric mitochondrial (Mi)-CK) and monomeric arginine kinase (AK). Considerable changes in the shape and the size of the molecules occurred upon binding of Mg-nucleotide or TSAC. The radius of gyration of Mi-CK was reduced from 55.6 A (free enzyme) to 48.9 A (enzyme plus Mg-ATP) and to 48.2 A (enzyme plus TSAC). M-CK showed similar changes from 28.0 A (free enzyme) to 25.6 A (enzyme plus Mg-ATP) and to 25.5 A (enzyme plus TSAC). Creatine alone did not lead to significant changes in the radii of gyration, nor did free ATP or ADP. AK also showed a change of the radius of gyration from 21.5 A (free enzyme) to 19.7 A (enzyme plus Mg-ATP), whereas with arginine alone only a minor change could be observed. The primary change in structure as seen with monomeric AK seems to be a Mg-nucleotide-induced domain movement relative to each other, whereas the effect of substrate may be of local order only. In CK, however, additional movements have to be involved.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism*
  • Algorithms
  • Animals
  • Arginine Kinase / chemistry*
  • Arginine Kinase / metabolism*
  • Chickens
  • Cloning, Molecular
  • Computer Simulation
  • Creatine Kinase / chemistry*
  • Creatine Kinase / metabolism*
  • Crystallography, X-Ray / methods
  • Dimerization
  • Escherichia coli
  • Isoenzymes
  • Mitochondria / enzymology
  • Mitochondria, Muscle / enzymology
  • Protein Binding
  • Protein Conformation*
  • Protein Structure, Secondary
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Sarcomeres / enzymology
  • Scattering, Radiation
  • X-Rays

Substances

  • Isoenzymes
  • Recombinant Proteins
  • Adenosine Triphosphate
  • Creatine Kinase
  • Arginine Kinase