2qvv
From Proteopedia
Porcine Liver Fructose-1,6-bisphosphatase cocrystallized with Fru-2,6-P2 and Zn2+, I(T)-state
Overview
Fructose-1,6-bisphosphatase (FBPase) operates at a control point in mammalian gluconeogenesis, being inhibited synergistically by fructose 2,6-bisphosphate (Fru-2,6-P(2)) and AMP. AMP and Fru-2,6-P(2) bind to allosteric and active sites, respectively, but the mechanism responsible for AMP/Fru-2,6-P(2) synergy is unclear. Demonstrated here for the first time is a global conformational change in porcine FBPase induced by Fru-2,6-P(2) in the absence of AMP. The Fru-2,6-P(2) complex exhibits a subunit pair rotation of 13 degrees from the R-state (compared with the 15 degrees rotation of the T-state AMP complex) with active site loops in the disengaged conformation. A three-state thermodynamic model in which Fru-2,6-P(2) drives a conformational change to a T-like intermediate state can account for AMP/Fru-2,6-P(2) synergism in mammalian FBPases. AMP and Fru-2,6-P(2) are not synergistic inhibitors of the Type I FBPase from Escherichia coli, and consistent with that model, the complex of E. coli FBPase with Fru-2,6-P(2) remains in the R-state with dynamic loops in the engaged conformation. Evidently in porcine FBPase, the actions of AMP at the allosteric site and Fru-2,6-P(2) at the active site displace engaged dynamic loops by distinct mechanisms, resulting in similar quaternary end-states. Conceivably, Type I FBPases from all eukaryotes may undergo similar global conformational changes in response to Fru-2,6-P(2) ligation.
About this Structure
2QVV is a Single protein structure of sequence from Sus scrofa. Full crystallographic information is available from OCA.
Reference
Structures of mammalian and bacterial fructose-1,6-bisphosphatase reveal the basis for synergism in AMP/fructose 2,6-bisphosphate inhibition., Hines JK, Chen X, Nix JC, Fromm HJ, Honzatko RB, J Biol Chem. 2007 Dec 7;282(49):36121-31. Epub 2007 Oct 12. PMID:17933867 Page seeded by OCA on Sun May 4 15:46:56 2008
