4i4i

Crystal Structure of Bacillus stearothermophilus Phosphofructokinase mutant T156A bound to PEP

spinqualitylabelsall models 4i4i, resolution 2.49Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4i4i is a 4 chain structure with sequence from Geobacillus stearothermophilus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: PEP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PFKA_GEOSE Catalyzes the phosphorylation of D-fructose 6-phosphate to fructose 1,6-bisphosphate by ATP, the first committing step of glycolysis.[HAMAP-Rule:MF_00339] Publication Abstract from PubMed Bacillus stearothermophilus PFK (BsPFK) is a homotetramer that is allosterically inhibited by phosphoenolpyruvate (PEP), which binds along one dimer-dimer interface. The substrate, fructose 6-phosphate (Fru-6-P), binds along the other dimer-dimer interface. Evans et al., observed that the inhibitor, phosphoglycolate, bound structure, when compared to the substrate and activator bound structure of wild-type BsPFK, exhibits a 7 degrees rotation about the substrate-binding interface, termed the quaternary shift [Schirmer, T., and Evans, P. R. (1990) Nature 343, 140-145]. We report that the variant D12A BsPFK exhibits a 100-fold increase in the binding affinity for PEP, a 50-fold decrease in the binding affinity for Fru-6-P, but an inhibitory coupling comparable to wild type. Crystal structures of the apo and PEP bound forms of D12A BsPFK have been determined (Protein Data Bank ID codes 4I36 and 4I7E, respectively), and both indicate a shifted structure similar to the inhibitor-bound structure of wild type. D12 does not directly bind to either substrate or inhibitor and is located along the substrate-binding interface. A conserved hydrogen bond between D12 and T156 forms across the substrate-binding subunit-subunit interface in the substrate-bound form of BsPFK. The variant T156A BsPFK, when compared to wild-type, shows a 30-fold increase in PEP binding affinity, a 17-fold decrease in Fru-6-P binding affinity, and an estimated coupling that is also approximately equal to wild-type. In addition, the T156A BsPFK crystal structure bound to PEP is reported (Protein Data Bank ID code 4I4I), and it exhibits a shifted structure similar to D12A BsPFK and the inhibitor-bound structure of wild type. The results suggest that main role of the quaternary shift may be to influence ligand binding and not to cause the heterotropic allosteric inhibition per se. Redefining the Role of the Quaternary Shift in Bacillus stearothermophilus Phosphofructokinase.,Mosser R, Reddy MC, Bruning JB, Sacchettini JC, Reinhart GD Biochemistry. 2013 Jul 16. PMID:23859543 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Phosphofructokinase 3D structures

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