2c54: Difference between revisions
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[[Image:2c54.gif|left|200px]] | [[Image:2c54.gif|left|200px]] | ||
'''GDP-MANNOSE-3', 5'-EPIMERASE (ARABIDOPSIS THALIANA), K178R, WITH GDP-BETA-L-GULOSE AND GDP-4-KETO-BETA-L-GULOSE BOUND IN ACTIVE SITE.''' | {{Structure | ||
|PDB= 2c54 |SIZE=350|CAPTION= <scene name='initialview01'>2c54</scene>, resolution 1.500Å | |||
|SITE= <scene name='pdbsite=AC1:Epe+Binding+Site+For+Chain+A'>AC1</scene> | |||
|LIGAND= <scene name='pdbligand=GKE:GUANOSINE+5'-DIPHOSPHATE-BETA-L-GULOSE'>GKE</scene>, <scene name='pdbligand=NAD:NICOTINAMIDE-ADENINE-DINUCLEOTIDE'>NAD</scene>, <scene name='pdbligand=EPE:4-(2-HYDROXYETHYL)-1-PIPERAZINE+ETHANESULFONIC+ACID'>EPE</scene> and <scene name='pdbligand=FMT:FORMIC ACID'>FMT</scene> | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/GDP-mannose_3,5-epimerase GDP-mannose 3,5-epimerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.1.3.18 5.1.3.18] | |||
|GENE= | |||
}} | |||
'''GDP-MANNOSE-3', 5'-EPIMERASE (ARABIDOPSIS THALIANA), K178R, WITH GDP-BETA-L-GULOSE AND GDP-4-KETO-BETA-L-GULOSE BOUND IN ACTIVE SITE.''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
2C54 is a [ | 2C54 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2C54 OCA]. | ||
==Reference== | ==Reference== | ||
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:[http:// | 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:[http://www.ncbi.nlm.nih.gov/pubmed/16366586 16366586] | ||
[[Category: Arabidopsis thaliana]] | [[Category: Arabidopsis thaliana]] | ||
[[Category: GDP-mannose 3,5-epimerase]] | [[Category: GDP-mannose 3,5-epimerase]] | ||
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[[Category: vitamin c]] | [[Category: vitamin c]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 16:10:59 2008'' | ||
Revision as of 17:10, 20 March 2008
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| , resolution 1.500Å | |||||||
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| Sites: | |||||||
| Ligands: | , , and | ||||||
| Activity: | GDP-mannose 3,5-epimerase, with EC number 5.1.3.18 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
GDP-MANNOSE-3', 5'-EPIMERASE (ARABIDOPSIS THALIANA), K178R, WITH GDP-BETA-L-GULOSE AND GDP-4-KETO-BETA-L-GULOSE BOUND IN ACTIVE SITE.
OverviewOverview
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.
About this StructureAbout this Structure
2C54 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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