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Interaction of calmodulin with the phosphofructokinase target sequence
Author(s) -
Martin Stephen R.,
Biekofsky Rodolfo R.,
Skinner Murray A.,
Guerrini Remo,
Salvadori Severo,
Feeney James,
Bayley Peter M.
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2004.10.023
Subject(s) - tetramer , calmodulin , phosphofructokinase , histidine , chemistry , titration , glycolysis , peptide , biochemistry , peptide sequence , heteronuclear single quantum coherence spectroscopy , stereochemistry , target peptide , enzyme , biophysics , nuclear magnetic resonance spectroscopy , biology , inorganic chemistry , gene
Ca 4 · calmodulin (Ca 4 · CaM) inhibits the glycolytic enzyme phosphofructokinase, by preventing formation of its active tetramer. Fluorescence titrations show that the affinity of complex formation of Ca 4 · 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. 1 H NMR pH titration indicates a marked increase in p K a 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 Ca 4 · CaM in regulation of the glycolytic pathway.