1hor
STRUCTURE AND CATALYTIC MECHANISM OF GLUCOSAMINE 6-PHOSPHATE DEAMINASE FROM ESCHERICHIA COLI AT 2.1 ANGSTROMS RESOLUTION
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OverviewOverview
BACKGROUND: 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 aldoseketose 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 A 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.
About this StructureAbout this Structure
1HOR is a Single protein structure of sequence from Escherichia coli with PO4 and AGP as ligands. Active as Glucosamine-6-phosphate deaminase, with EC number 3.5.99.6 Full crystallographic information is available from OCA.
ReferenceReference
Structure and catalytic mechanism of glucosamine 6-phosphate deaminase from Escherichia coli at 2.1 A resolution., Oliva G, Fontes MR, Garratt RC, Altamirano MM, Calcagno ML, Horjales E, Structure. 1995 Dec 15;3(12):1323-32. PMID:8747459
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