1hor: Difference between revisions

Revision as of 19:04, 2 May 2008

STRUCTURE AND CATALYTIC MECHANISM OF GLUCOSAMINE 6-PHOSPHATE DEAMINASE FROM ESCHERICHIA COLI AT 2.1 ANGSTROMS RESOLUTION

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. 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 Page seeded by OCA on Fri May 2 19:04:24 2008

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OCA

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 [[Image:1hor.gif|left|200px]]
- {{Structure
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-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Glucosamine-6-phosphate_deaminase Glucosamine-6-phosphate deaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.99.6 3.5.99.6] </span>
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-}}
 '''STRUCTURE AND CATALYTIC MECHANISM OF GLUCOSAMINE 6-PHOSPHATE DEAMINASE FROM ESCHERICHIA COLI AT 2.1 ANGSTROMS RESOLUTION'''
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 [[Category: Horjales, E.]]
 [[Category: Oliva, G.]]
-[[Category: intramolecular oxidoreductase deaminase]]
+[[Category: Intramolecular oxidoreductase deaminase]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 19:04:24 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 21:08:27 2008''