1bu6

CRYSTAL STRUCTURES OF ESCHERICHIA COLI GLYCEROL KINASE AND THE MUTANT A65T IN AN INACTIVE TETRAMER: CONFORMATIONAL CHANGES AND IMPLICATIONS FOR ALLOSTERIC REGULATION

spinqualitylabelsall models 1bu6, resolution 2.37Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1bu6 is a 4 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.37Å Ligands: GOL, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function GLPK_ECOLI Key enzyme in the regulation of glycerol uptake and metabolism.[HAMAP-Rule:MF_00186] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed BACKGROUND: Glycerol kinase (GK) from Escherichia coli is a velocity-modulated (V system) enzyme that has three allosteric effectors with independent mechanisms: fructose-1,6-bisphosphate (FBP); the phosphocarrier protein IIAGlc; and adenosine nucleotides. The enzyme exists in solution as functional dimers that associate reversibly to form tetramers. GK is a member of a superfamily of ATPases that share a common ATPase domain and are thought to undergo a large conformational change as an intrinsic step in their catalytic cycle. Members of this family include actin, hexokinase and the heat shock protein hsc70. RESULTS: We report here the crystal structures of GK and a mutant of GK (Ala65-->Thr) in complex with glycerol and ADP. Crystals of both enzymes contain the same 222 symmetric tetramer. The functional dimer is identical to that described previously for the IIAGlc-GK complex structure. The tetramer interface is significantly different, however, with a relative 22.3 degrees rotation and 6.34 A translation of one functional dimer. The overall monomer structure is unchanged except for two regions: the IIAGlc-binding site undergoes a structural rearrangement and residues 230-236 become ordered and bind orthophosphate at the tetramer interface. We also report the structure of a second mutant of GK (IIe474-->Asp) in complex with IIAGlc; this complex crystallized isomorphously to the wild type IIAGlc-GK complex. Site-directed mutants of GK with substitutions at the IIAGlc-binding site show significantly altered kinetic and regulatory properties, suggesting that the conformation of the binding site is linked to the regulation of activity. CONCLUSIONS: We conclude that the new tetramer structure presented here is an inactive form of the physiologically relevant tetramer. The structure and location of the orthophosphate-binding site is consistent with it being part of the FBP-binding site. Mutational analysis and the structure of the IIAGlc-GK(IIe474-->Asp) complex suggest the conformational transition of the IIAGlc-binding site to be an essential aspect of IIAGlc regulation. Glycerol kinase from Escherichia coli and an Ala65-->Thr mutant: the crystal structures reveal conformational changes with implications for allosteric regulation.,Feese MD, Faber HR, Bystrom CE, Pettigrew DW, Remington SJ Structure. 1998 Nov 15;6(11):1407-18. PMID:9817843 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Glycerol kinase

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