1hot: Difference between revisions
New page: left|200px<br /><applet load="1hot" size="450" color="white" frame="true" align="right" spinBox="true" caption="1hot, resolution 2.4Å" /> '''GLUCOSAMINE 6-PHOSPHA... |
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[[Image:1hot.gif|left|200px]]<br /><applet load="1hot" size=" | [[Image:1hot.gif|left|200px]]<br /><applet load="1hot" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1hot, resolution 2.4Å" /> | caption="1hot, resolution 2.4Å" /> | ||
'''GLUCOSAMINE 6-PHOSPHATE DEAMINASE COMPLEXED WITH THE ALLOSTERIC ACTIVATOR N-ACETYL-GLUCOSAMINE-6-PHOSPHATE'''<br /> | '''GLUCOSAMINE 6-PHOSPHATE DEAMINASE COMPLEXED WITH THE ALLOSTERIC ACTIVATOR N-ACETYL-GLUCOSAMINE-6-PHOSPHATE'''<br /> | ||
==Overview== | ==Overview== | ||
BACKGROUND: Glucosamine 6-phosphate deaminase from Escherichia coli is an | 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 Structure== | ==About this Structure== | ||
1HOT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with PO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [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] Full crystallographic information is available from [http:// | 1HOT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=PO4:'>PO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [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] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HOT OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Glucosamine-6-phosphate deaminase]] | [[Category: Glucosamine-6-phosphate deaminase]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Altamirano, M | [[Category: Altamirano, M M.]] | ||
[[Category: Calcagno, M | [[Category: Calcagno, M L.]] | ||
[[Category: Fontes, M | [[Category: Fontes, M L.]] | ||
[[Category: Garratt, R.]] | [[Category: Garratt, R.]] | ||
[[Category: Horjales, E.]] | [[Category: Horjales, E.]] | ||
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[[Category: isomerase]] | [[Category: isomerase]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:03:20 2008'' | ||
Revision as of 11:03, 21 February 2008
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GLUCOSAMINE 6-PHOSPHATE DEAMINASE COMPLEXED WITH THE ALLOSTERIC ACTIVATOR N-ACETYL-GLUCOSAMINE-6-PHOSPHATE
Overview
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 Structure
1HOT is a Single protein structure of sequence from Escherichia coli with PO4 as ligand. Active as Glucosamine-6-phosphate deaminase, with EC number 3.5.99.6 Full crystallographic information is available from OCA.
Reference
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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