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2ou4
From Proteopedia
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| - | [[Image:2ou4.jpg|left|200px]] | + | [[Image:2ou4.jpg|left|200px]] |
| - | + | ||
| - | '''Crystal structure of D-tagatose 3-epimerase from Pseudomonas cichorii''' | + | {{Structure |
| + | |PDB= 2ou4 |SIZE=350|CAPTION= <scene name='initialview01'>2ou4</scene>, resolution 2.50Å | ||
| + | |SITE= | ||
| + | |LIGAND= <scene name='pdbligand=MN:MANGANESE (II) ION'>MN</scene> | ||
| + | |ACTIVITY= | ||
| + | |GENE= | ||
| + | }} | ||
| + | |||
| + | '''Crystal structure of D-tagatose 3-epimerase from Pseudomonas cichorii''' | ||
| + | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 2OU4 is a [ | + | 2OU4 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_cichorii Pseudomonas cichorii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2OU4 OCA]. |
==Reference== | ==Reference== | ||
| - | Crystal structures of D-tagatose 3-epimerase from Pseudomonas cichorii and its complexes with D-tagatose and D-fructose., Yoshida H, Yamada M, Nishitani T, Takada G, Izumori K, Kamitori S, J Mol Biol. 2007 Nov 23;374(2):443-53. Epub 2007 Sep 19. PMID:[http:// | + | Crystal structures of D-tagatose 3-epimerase from Pseudomonas cichorii and its complexes with D-tagatose and D-fructose., Yoshida H, Yamada M, Nishitani T, Takada G, Izumori K, Kamitori S, J Mol Biol. 2007 Nov 23;374(2):443-53. Epub 2007 Sep 19. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/17936787 17936787] |
[[Category: Pseudomonas cichorii]] | [[Category: Pseudomonas cichorii]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
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[[Category: isomerase]] | [[Category: isomerase]] | ||
| - | ''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 18:04:29 2008'' |
Revision as of 16:04, 20 March 2008
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| , resolution 2.50Å | |||||||
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| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal structure of D-tagatose 3-epimerase from Pseudomonas cichorii
Overview
Pseudomonas cichoriiid-tagatose 3-epimerase (P. cichoriid-TE) can efficiently catalyze the epimerization of not only d-tagatose to d-sorbose, but also d-fructose to d-psicose, and is used for the production of d-psicose from d-fructose. The crystal structures of P. cichoriid-TE alone and in complexes with d-tagatose and d-fructose were determined at resolutions of 1.79, 2.28, and 2.06 A, respectively. A subunit of P. cichoriid-TE adopts a (beta/alpha)(8) barrel structure, and a metal ion (Mn(2+)) found in the active site is coordinated by Glu152, Asp185, His211, and Glu246 at the end of the beta-barrel. P. cichoriid-TE forms a stable dimer to give a favorable accessible surface for substrate binding on the front side of the dimer. The simulated omit map indicates that O2 and O3 of d-tagatose and/or d-fructose coordinate Mn(2+), and that C3-O3 is located between carboxyl groups of Glu152 and Glu246, supporting the previously proposed mechanism of deprotonation/protonation at C3 by two Glu residues. Although the electron density is poor at the 4-, 5-, and 6-positions of the substrates, substrate-enzyme interactions can be deduced from the significant electron density at O6. The O6 possibly interacts with Cys66 via hydrogen bonding, whereas O4 and O5 in d-tagatose and O4 in d-fructose do not undergo hydrogen bonding to the enzyme and are in a hydrophobic environment created by Phe7, Trp15, Trp113, and Phe248. Due to the lack of specific interactions between the enzyme and its substrates at the 4- and 5-positions, P. cichoriid-TE loosely recognizes substrates in this region, allowing it to efficiently catalyze the epimerization of d-tagatose and d-fructose (C4 epimer of d-tagatose) as well. Furthermore, a C3-O3 proton-exchange mechanism for P. cichoriid-TE is suggested by X-ray structural analysis, providing a clear explanation for the regulation of the ionization state of Glu152 and Glu246.
About this Structure
2OU4 is a Single protein structure of sequence from Pseudomonas cichorii. Full crystallographic information is available from OCA.
Reference
Crystal structures of D-tagatose 3-epimerase from Pseudomonas cichorii and its complexes with D-tagatose and D-fructose., Yoshida H, Yamada M, Nishitani T, Takada G, Izumori K, Kamitori S, J Mol Biol. 2007 Nov 23;374(2):443-53. Epub 2007 Sep 19. PMID:17936787
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