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| [[Image:2q8m.jpg|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_2q8m| PDB=2q8m | SCENE= }} | | {{STRUCTURE_2q8m| PDB=2q8m | SCENE= }} |
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| '''T-like Fructose-1,6-bisphosphatase from Escherichia coli with AMP, Glucose 6-phosphate, and Fructose 1,6-bisphosphate bound'''
| | ===T-like Fructose-1,6-bisphosphatase from Escherichia coli with AMP, Glucose 6-phosphate, and Fructose 1,6-bisphosphate bound=== |
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| ==Overview==
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| Allosteric activation of fructose-1,6-bisphosphatase (FBPase) from Escherichia coli by phosphoenolpyruvate implies rapid feed-forward activation of gluconeogenesis in heterotrophic bacteria. But how do such bacteria rapidly down-regulate an activated FBPase in order to avoid futile cycling? Demonstrated here is the allosteric inhibition of E. coli FBPase by glucose 6-phosphate (Glc-6-P), the first metabolite produced upon glucose transport into the cell. FBPase undergoes a quaternary transition from the canonical R-state to a T-like state in response to Glc-6-P and AMP ligation. By displacing Phe(15), AMP binds to an allosteric site comparable with that of mammalian FBPase. Relative movements in helices H1 and H2 perturb allosteric activator sites for phosphoenolpyruvate. Glc-6-P binds to allosteric sites heretofore not observed in previous structures, perturbing subunits that in pairs form complete active sites of FBPase. Glc-6-P and AMP are synergistic inhibitors of E. coli FBPase, placing AMP/Glc-6-P inhibition in bacteria as a possible evolutionary predecessor to AMP/fructose 2,6-bisphosphate inhibition in mammalian FBPases. With no exceptions, signature residues of allosteric activation appear in bacterial sequences along with key residues of the Glc-6-P site. FBPases in such organisms may be components of metabolic switches that allow rapid changeover between gluconeogenesis and glycolysis in response to nutrient availability.
| | The line below this paragraph, {{ABSTRACT_PUBMED_17567577}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 17567577 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_17567577}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Proteobacteria]] | | [[Category: Proteobacteria]] |
| [[Category: X-ray diffraction]] | | [[Category: X-ray diffraction]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 14:32:28 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 19:23:22 2008'' |
