Phosphofructokinase domain structures

Figure 16.19. Domain Structure of the Bifunctional Enzyme Phosphofructokinase 2. The kinase domain (purple) is fused to the phosphatase domain (red). The kinase domain is a P-loop NTP hydrolase domain, as indicated by the purple shading (Section 9.4.4). The bar represents the amino acid sequence of the enzyme.

Figure 16.15 Structure of phosphofructokinase. The structure of phosphofructokinase from E. cofi comprises a tetramer of four identical subunits. Notice the separation of the catalytic and allosteric sites. Each subunit of the human liver enzyme consists of two domains that are similar to the E. coli enzyme. [Drawn from IPFK.pdb,]...

Describe the allosteric regulation of phosphofructokinase. Explain the role of fructose 2,6-bisphosphate in its regulation. Describe the fused-domain structure of phosphofructokinase 2 (PFK2)/fructose bisphosphatase 2 that forms and degrades fructose 2,6-bisphosphate. 

Figure 6.25 Schematic diagram of the structure of one dimer of phosphofructokinase. Each polypeptide chain is folded Into two domains (blue and red, and green and brown), each of which has an oi/p structure. Helices are labeled A to M and p strands 1 to 11 from the amino terminus of one polypeptide chain, and respectively from A to M and 1 to 11 for the second polypeptide chain. The binding sites of substrate and effector molecules are schematically marked In gray. The effector site of one subunit is linked to the active site of the other subunit of the dimer through the 6-F loop between helix F and strand 6. (Adapted from T. Schlrmer and P.R. Evans, Nature 343 140-145, 1990.)...

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