PMID:15848164
| Citation |
Caniuguir, A, Cabrera, R, Báez, M, Vásquez, CC, Babul, J and Guixé, V (2005) Role of Cys-295 on subunit interactions and allosteric regulation of phosphofructokinase-2 from Escherichia coli. FEBS Lett. 579:2313-8 |
|---|---|
| Abstract |
In a previous work, chemical modification of Cys-238 of Escherichia coli Pfk-2 raised concerns on the importance of the dimeric state of Pfk-2 for enzyme activity, whereas modification of Cys-295 impaired the enzymatic activity and the MgATP-induced tetramerization of the enzyme. The results presented here demonstrate that the dimeric state of Pfk-2 is critical for the stability and the activity of the enzyme. The replacement of Cys-238 by either Ala or Phe shows no effect on the kinetic parameters, allosteric inhibition, dimer stability and oligomeric structure of Pfk-2. However, the mutation of Cys-295 by either Ala or Phe provokes a decrease in the k(cat) value and an increment in the K(m) values for both substrates. We suggest that the Cys-295 residue participates in intersubunit interactions in the tetramer since the Cys-295-Phe mutant exhibits higher tetramer stability, which in turn results in an increase in the fructose-6-P concentration required for the reversal of the MgATP inhibition relative to the wild type enzyme. |
| Links |
PubMed Online version:10.1016/j.febslet.2005.02.078 |
| Keywords |
Allosteric Regulation; Cysteine/genetics; Cysteine/metabolism; Dimerization; Enzyme Inhibitors/pharmacology; Enzyme Stability/drug effects; Escherichia coli/enzymology; Escherichia coli/genetics; Fructosephosphates/metabolism; Guanidine/pharmacology; Kinetics; Mutation/genetics; Phosphofructokinase-2/antagonists & inhibitors; Phosphofructokinase-2/chemistry; Phosphofructokinase-2/genetics; Phosphofructokinase-2/metabolism; Protein Denaturation/drug effects; Protein Folding; Protein Subunits/chemistry; Protein Subunits/genetics; Protein Subunits/metabolism; Substrate Specificity |
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