Interaction of calmodulin with the phosphofructokinase target sequence

FEBS Lett. 2004 Nov 5;577(1-2):284-8. doi: 10.1016/j.febslet.2004.10.023.


Ca4.calmodulin (Ca4.CaM) inhibits the glycolytic enzyme phosphofructokinase, by preventing formation of its active tetramer. Fluorescence titrations show that the affinity of complex formation of Ca4.CaM with the key 21-residue target peptide increases 1000-fold from pH 9.0 to 4.8, suggesting the involvement of histidine and carboxylic acid residues. 1H NMR pH titration indicates a marked increase in pKa of the peptide histidine on complex formation and HSQC spectra show related pH-dependent changes in the conformation of the complex. This unusually strong sensitivity of a CaM-target complex to pH suggests a potential functional role for Ca4.CaM in regulation of the glycolytic pathway.

MeSH terms

  • Animals
  • Calcium / metabolism
  • Calmodulin / metabolism*
  • Drosophila melanogaster
  • Hydrogen-Ion Concentration
  • Nuclear Magnetic Resonance, Biomolecular
  • Phosphofructokinases / chemistry
  • Phosphofructokinases / metabolism*
  • Protein Binding
  • Recombinant Proteins / metabolism
  • Spectrometry, Fluorescence


  • Calmodulin
  • Recombinant Proteins
  • Phosphofructokinases
  • Calcium