1gpu: Difference between revisions
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[[Image:1gpu.gif|left|200px]] | [[Image:1gpu.gif|left|200px]] | ||
'''TRANSKETOLASE COMPLEX WITH REACTION INTERMEDIATE''' | {{Structure | ||
|PDB= 1gpu |SIZE=350|CAPTION= <scene name='initialview01'>1gpu</scene>, resolution 1.86Å | |||
|SITE= <scene name='pdbsite=AC1:Thd+Binding+Site+For+Chain+B'>AC1</scene> | |||
|LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene> and <scene name='pdbligand=THD:2-[3-[(4-AMINO-2-METHYL-5-PYRIMIDINYL)METHYL]-2-(1,2-DIHYDROXYETHYL)-4-METHYL-1,3-THIAZOL-3-IUM-5-YL]ETHYL TRIHYDROGEN DIPHOSPHATE'>THD</scene> | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/Transketolase Transketolase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.2.1.1 2.2.1.1] | |||
|GENE= | |||
}} | |||
'''TRANSKETOLASE COMPLEX WITH REACTION INTERMEDIATE''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1GPU is a [ | 1GPU is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GPU OCA]. | ||
==Reference== | ==Reference== | ||
Snapshot of a key intermediate in enzymatic thiamin catalysis: crystal structure of the alpha-carbanion of (alpha,beta-dihydroxyethyl)-thiamin diphosphate in the active site of transketolase from Saccharomyces cerevisiae., Fiedler E, Thorell S, Sandalova T, Golbik R, Konig S, Schneider G, Proc Natl Acad Sci U S A. 2002 Jan 22;99(2):591-5. Epub 2002 Jan 2. PMID:[http:// | Snapshot of a key intermediate in enzymatic thiamin catalysis: crystal structure of the alpha-carbanion of (alpha,beta-dihydroxyethyl)-thiamin diphosphate in the active site of transketolase from Saccharomyces cerevisiae., Fiedler E, Thorell S, Sandalova T, Golbik R, Konig S, Schneider G, Proc Natl Acad Sci U S A. 2002 Jan 22;99(2):591-5. Epub 2002 Jan 2. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/11773632 11773632] | ||
[[Category: Saccharomyces cerevisiae]] | [[Category: Saccharomyces cerevisiae]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
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[[Category: transferase(ketone residues)]] | [[Category: transferase(ketone residues)]] | ||
''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 11:26:22 2008'' | ||
Revision as of 12:26, 20 March 2008
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| , resolution 1.86Å | |||||||
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| Sites: | |||||||
| Ligands: | and | ||||||
| Activity: | Transketolase, with EC number 2.2.1.1 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
TRANSKETOLASE COMPLEX WITH REACTION INTERMEDIATE
OverviewOverview
Kinetic and spectroscopic data indicated that addition of the donor substrate hydroxypyruvate to the thiamin diphosphate (ThDP)-dependent enzyme transketolase (TK) led to the accumulation of the alpha-carbanion/enamine of (alpha,beta-dihydroxyethyl) ThDP, the key reaction intermediate in enzymatic thiamin catalysis. The three-dimensional structure of this intermediate trapped in the active site of yeast TK was determined to 1.9-A resolution by using cryocrystallography. The electron density suggests a planar alpha-carbanion/enamine intermediate having the E-configuration. The reaction intermediate is firmly held in place through direct hydrogen bonds to His-103 and His-481 and an indirect hydrogen bond via a water molecule to His-69. The 4-NH(2) group of the amino-pyrimidine ring of ThDP is within 3 A distance to the alpha-hydroxy oxygen atom of the dihydroxyethyl moiety but at an angle unfavorable for a strong hydrogen bond. No structural changes occur in TK on formation of the reaction intermediate, suggesting that the active site is poised for catalysis and conformational changes during the enzyme reaction are not very likely. The intermediate is present with high occupancy in both active sites, arguing against previous proposals of half-of-the-sites reactivity in yeast TK.
About this StructureAbout this Structure
1GPU is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
ReferenceReference
Snapshot of a key intermediate in enzymatic thiamin catalysis: crystal structure of the alpha-carbanion of (alpha,beta-dihydroxyethyl)-thiamin diphosphate in the active site of transketolase from Saccharomyces cerevisiae., Fiedler E, Thorell S, Sandalova T, Golbik R, Konig S, Schneider G, Proc Natl Acad Sci U S A. 2002 Jan 22;99(2):591-5. Epub 2002 Jan 2. PMID:11773632
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