2q8m

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spinqualitylabelsall models 2q8m, resolution 2.050Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

T-like Fructose-1,6-bisphosphatase from Escherichia coli with AMP, Glucose 6-phosphate, and Fructose 1,6-bisphosphate bound

Overview

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.

About this Structure

2Q8M is a Single protein structure of sequence from Shigella boydii with BG6, FBP, MG, CL and AMP as ligands. Active as Fructose-bisphosphatase, with EC number 3.1.3.11 Full crystallographic information is available from OCA.

Reference

Structure of Inhibited Fructose-1,6-bisphosphatase from Escherichia coli: DISTINCT ALLOSTERIC INHIBITION SITES FOR AMP AND GLUCOSE 6-PHOSPHATE AND THE CHARACTERIZATION OF A GLUCONEOGENIC SWITCH., Hines JK, Kruesel CE, Fromm HJ, Honzatko RB, J Biol Chem. 2007 Aug 24;282(34):24697-706. Epub 2007 Jun 13. PMID:17567577

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