1H-NMR studies on nucleotide binding to the sarcoplasmic reticulum Ca2+ ATPase. Determination of the conformations of bound nucleotides by the measurement of proton-proton transferred nuclear Overhauser enhancements

Eur J Biochem. 1982 Nov;128(1):113-17.


The glycosidic bond torsion angles and the conformations of the ribose of Mg2+ATP, Mg2+ADP and Mg2+AdoPP[NH]P (magnesium adenosine 5'-[beta, gamma-imido]triphosphate) bound to Ca2+ATPase, both native and modified with fluorescein isothiocyanate (FITC), in intact sarcoplasmic reticulum have been determined by the measurement of proton-proton transferred nuclear Overhauser enhancements by 1H-NMR spectroscopy. This method shows clearly the existence of a low-affinity ATP binding site after modification of the high-affinity site with FITC. For all three nucleotides bound to both the high-affinity (catalytic) site and the low-affinity site, we find that the conformation about the glycosidic bond is anti, the conformation of the ribose 3'-endo of the N type and the conformation about the ribose C4'-C5' bond either gauche-trans or trans-gauche. The values for the glycosidic bond torsion angles chi (O4'-C1'-N9-C4) for Mg2+ATP, Mg2+ADP and Mg2+AdoPP[NH]P bound to the low-affinity site of FITC-modified Ca2+ATPase are approximately equal to 270 degrees, approximately equal to 260 degrees and approximately equal to 240 degrees respectively. In the case of the nucleotides bound to the high-affinity (catalytic) site of native Ca2+ATPase, chi lies in the range 240-280 degrees.

MeSH terms

  • Adenosine Diphosphate / metabolism
  • Adenosine Triphosphate / metabolism
  • Adenylyl Imidodiphosphate / metabolism
  • Animals
  • Calcium-Transporting ATPases / metabolism*
  • Energy Transfer
  • Magnetic Resonance Spectroscopy
  • Molecular Conformation
  • Nucleotides / metabolism*
  • Protein Binding
  • Protons
  • Rabbits
  • Sarcoplasmic Reticulum / enzymology*


  • Nucleotides
  • Protons
  • Adenylyl Imidodiphosphate
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • Calcium-Transporting ATPases