The crystal structure of rabbit phosphoglucose isomerase complexed with 5-phospho-D-arabinonohydroxamic acid.
Phosphoglucose isomerase (EC ) catalyzes the second step in glycolysis, the reversible isomerization of D-glucose 6-phosphate to D-fructose 6-phosphate. The reaction mechanism involves acid-base catalysis with proton transfer and proceeds through a cis-enediol(ate) intermediate. 5-Phospho-D-arabinonohydroxamic acid (5PAH) is a synthetic small molecule that resembles the reaction intermediate, differing only in that it has a nitrogen atom in place of C1. Hence, 5PAH is the best inhibitor of the isomerization reaction reported to date with a K(i) of 2 x 10(-7) M. Here we report the crystal structure of rabbit phosphoglucose isomerase complexed with 5PAH at 1.9 A resolution. The interaction of 5PAH with amino acid residues in the enzyme active site supports a model of the catalytic mechanism in which Glu-357 transfers a proton between C1 and C2 and Arg-272 helps stabilize the intermediate. It also suggests a mechanism for proton transfer between O1 and O2.
Arsenieva
Diana
D
Laboratory for Molecular Biology, MC567, Department of Biological Sciences, University of Illinois, Chicago, IL 60607, USA.
Hardre
Renaud
R
Salmon
Laurent
L
Jeffery
Constance J
CJ
D000818:Animals; D001665:Binding Sites; D002384:Catalysis; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D005956:Glucose-6-Phosphate Isomerase / Q000737:chemistry*; D018698:Glutamic Acid / Q000737:chemistry; D006877:Hydroxamic Acids / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D018482:Muscle, Skeletal / Q000201:enzymology; D009584:Nitrogen / Q000737:chemistry; D011485:Protein Binding; D011817:Rabbits; D013403:Sugar Phosphates / Q000737:chemistry*
C456025:5-phosphoarabinonohydroxamic acid; D006877:Hydroxamic Acids; D013403:Sugar Phosphates; D018698:Glutamic Acid; D005956:Glucose-6-Phosphate Isomerase; D009584:Nitrogen