Send to

Choose Destination
Biochemistry. 2009 Dec 29;48(51):12323-8. doi: 10.1021/bi901456p.

Disentangling the web of allosteric communication in a homotetramer: heterotropic inhibition in phosphofructokinase from Escherichia coli.

Author information

Department of Biochemistry and Biophysics, Texas A&M University and Texas AgriLife Research, College Station, Texas 77843-2128, USA.


This study quantifies the contribution of each of the four unique inhibiting heterotropic interactions between the allosteric inhibitor, phosphoenolpyruvate (PEP), and the substrate, fructose 6-phosphate (Fru-6-P), in phosphofructokinase from Escherichia coli (EcPFK). The unique heterotropic interactions, previously labeled by the distances between ligand binding sites, were isolated independently by constructing hybrid tetramers. Of the four unique heterotropic PEP-Fru-6-P interactions, the 45 A interaction contributed 25%, the 30 A interaction contributed 31%, and the 23 A interaction contributed 42% of the total PEP inhibition. The 33 A interaction actually causes a small activation of Fru-6-P binding by PEP and therefore contributed -8% of the total observed PEP inhibition. The pattern of relative contribution to PEP inhibition from each interaction in EcPFK does not follow the same pattern seen in MgADP activation of EcPFK. This observation supports the conclusion that although PEP and MgADP bind to the same site, they do not use the same communication pathways to influence the active site. The pattern of relative contribution describing PEP inhibition observed in this study also does not follow the pattern determined for PEP inhibition in phosphofructokinase from Bacillus stearothermophilus, suggesting that these two highly homologous isoforms are not inhibited in the same manner by PEP.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for American Chemical Society Icon for PubMed Central
Loading ...
Support Center