2c5e: Difference between revisions

Revision as of 17:12, 27 July 2008

This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.

File:2c5e.png

Template:STRUCTURE 2c5e

GDP-MANNOSE-3', 5'-EPIMERASE (ARABIDOPSIS THALIANA), K217A, WITH GDP-ALPHA-D-MANNOSE BOUND IN THE ACTIVE SITE.GDP-MANNOSE-3', 5'-EPIMERASE (ARABIDOPSIS THALIANA), K217A, WITH GDP-ALPHA-D-MANNOSE BOUND IN THE ACTIVE SITE.

Template:ABSTRACT PUBMED 16366586

About this StructureAbout this Structure

2C5E is a Single protein structure of sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA.

ReferenceReference

Structure and function of GDP-mannose-3',5'-epimerase: an enzyme which performs three chemical reactions at the same active site., Major LL, Wolucka BA, Naismith JH, J Am Chem Soc. 2005 Dec 28;127(51):18309-20. PMID:16366586

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Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

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 {{STRUCTURE_2c5e|  PDB=2c5e  |  SCENE=  }}
-'''GDP-MANNOSE-3', 5'-EPIMERASE (ARABIDOPSIS THALIANA), K217A, WITH GDP-ALPHA-D-MANNOSE BOUND IN THE ACTIVE SITE.'''
+===GDP-MANNOSE-3', 5'-EPIMERASE (ARABIDOPSIS THALIANA), K217A, WITH GDP-ALPHA-D-MANNOSE BOUND IN THE ACTIVE SITE.===
-==Overview==
+<!--
-GDP-mannose-3',5'-epimerase (GME) from Arabidopsis thaliana catalyzes the epimerization of both the 3' and 5' positions of GDP-alpha-D-mannose to yield GDP-beta-L-galactose. Production of the C5' epimer of GDP-alpha-D-mannose, GDP-beta-L-gulose, has also been reported. The reaction occurs as part of vitamin C biosynthesis in plants. We have determined structures of complexes of GME with GDP-alpha-D-mannose, GDP-beta-L-galactose, and a mixture of GDP-beta-L-gulose with GDP-beta-L-4-keto-gulose to resolutions varying from 2.0 to 1.4 A. The enzyme has the classical extended short-chain dehydratase/reductase (SDR) fold. We have confirmed that GME establishes an equilibrium between two products, GDP-beta-L-galactose and GDP-beta-L-gulose. The reaction proceeds by C4' oxidation of GDP-alpha-D-mannose followed by epimerization of the C5' position to give GDP-beta-L-4-keto-gulose. This intermediate is either reduced to give GDP-beta-L-gulose or the C3' position is epimerized to give GDP-beta-L-4-keto-galactose, then C4' is reduced to GDP-beta-L-galactose. The combination of oxidation, epimerization, and reduction in a single active site is unusual. Structural analysis coupled to site-directed mutagenesis suggests C145 and K217 as the acid/base pair responsible for both epimerizations. On the basis of the structure of the GDP-beta-L-gulose/GDP-beta-L-4-keto-gulose co-complex, we predict that a ring flip occurs during the first epimerization and that a boat intermediate is likely for the second epimerization. Comparison of GME with other SDR enzymes known to abstract a protein alpha to the keto function of a carbohydrate identifies key common features.
+The line below this paragraph, {{ABSTRACT_PUBMED_16366586}}, adds the Publication Abstract to the page
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+{{ABSTRACT_PUBMED_16366586}}
 ==About this Structure==
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 [[Category: Short chain dehydratase/reductase]]
 [[Category: Vitamin c]]
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