Oliva, GlauciusFontes, Marcos R.M. [UNESP]Garratt, Richard C.Altamirano, Myriam M.Calcagno, Mario L.Horjales, Eduardo2014-05-272014-05-271995-12-01Structure, v. 3, n. 12, p. 1323-1332, 1995.0969-2126http://hdl.handle.net/11449/64662Background: Glucosamine 6-phosphate deaminase from Escherichia coli is an allosteric hexameric enzyme which catalyzes the reversible conversion of D-glucosamine 6-phosphate into D-fructose 6-phosphate and ammonium ion and is activated by N-acetyl-D-glucosamine 6-phosphate. Mechanistically, it belongs to the group of aldose-ketose isomerases, but its reaction also accomplishes a simultaneous amination/deamination. The determination of the structure of this protein provides fundamental knowledge for understanding its mode of action and the nature of allosteric conformational changes that regulate its function. Results: The crystal structure of glucosamine 6-phosphate deaminase with bound phosphate ions is presented at 2.1 Å resolution together with the refined structures of the enzyme in complexes with its allosteric activator and with a competitive inhibitor. The protein fold can be described as a modified NAD-binding domain. Conclusions: From the similarities between the three presented structures, it is concluded that these represent the enzymatically active R state conformer. A mechanism for the deaminase reaction is proposed. It comprises steps to open the pyranose ring of the substrate and a sequence of general base-catalyzed reactions to bring about isomerization and deamination, with Asp72 playing a key role as a proton exchanger.1323-1332engα/β open structureAldose-ketose isomeraseAllosteric enzymeNAD-binding domain2 deoxy 2 aminoglucitol 6 phosphate2-deoxy-2-aminoglucitol-6-phosphatebacterial proteindrug derivativeenzyme inhibitorepimerasefructose 6 phosphatefructose phosphatefructose-6-phosphateglucosamineglucosamine 6 phosphateglucosamine 6 phosphate isomeraseglucosamine 6-phosphateglucosamine-6-phosphate isomeraseglucose 6 phosphateglucose phosphateisomerasenicotinamide adenine dinucleotidephosphatesorbitolsugar phosphateallosterismbinding sitebiosynthesiscatalysischemical structurechemistrydrug antagonismenzymologyEscherichia colimacromoleculemetabolismprotein conformationX ray crystallographyAldose-Ketose IsomerasesAllosteric RegulationBacterial ProteinsBinding SitesCarbohydrate EpimerasesCatalysisCrystallography, X-RayEnzyme InhibitorsFructosephosphatesGlucosamineGlucose-6-PhosphateGlucosephosphatesMacromolecular SubstancesModels, MolecularNADPhosphatesProtein ConformationSorbitolSugar PhosphatesBacteria (microorganisms)Artigo10.1016/S0969-2126(01)00270-2Acesso aberto2-s2.0-00296460952-s2.0-0029646095.pdf