Crystal structure of rabbit phosphoglucose isomerase complexed with 5-phospho-D-arabinonate identifies the role of Glu357 in catalysis.
Phosphoglucose isomerase (PGI; E.C. 5.3.1.9) catalyzes the second step in glycolysis, the interconversion of D-glucose-6-phosphate and D-fructose-6-phosphate. We determined the X-ray crystal structure of rabbit PGI complexed with a competitive inhibitor of isomerase activity, 5-phospho-D-arabinonate (5PAA), at 1.9 A resolution. 5PAA is a better mimic of the proposed cis-enediol(ate) intermediate than 6-phospho-D-gluconate, which was used in a previously reported crystal structure of rabbit PGI. The orientation of 5PAA bound in the enzyme active site predicts that active site residue Glu357 is the residue that transfers a proton between C2 and C1 of the proposed cis-enediol(ate) intermediate. Amino acid residues Arg272 and Lys210 are predicted to be involved in stabilizing the negative charge of the intermediate.
Jeffery
C J
CJ
Laboratory for Molecular Biology, MC567, Department of Biology, University of Illinois at Chicago, Chicago, IL 60607, USA. cjeffery@uic.edu
Hardré
R
R
Salmon
L
L
D000818:Animals; D001667:Binding, Competitive; D002384:Catalysis; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000378:metabolism; D001411:Geobacillus stearothermophilus / Q000201:enzymology; D005956:Glucose-6-Phosphate Isomerase / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D018698:Glutamic Acid / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D018482:Muscle, Skeletal / Q000201:enzymology; D010428:Pentosephosphates / Q000737:chemistry* / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D004791:Enzyme Inhibitors; D010428:Pentosephosphates; D010710:Phosphates; D018698:Glutamic Acid; C012188:arabinonate-5-phosphate; D005956:Glucose-6-Phosphate Isomerase