2qul
From Proteopedia
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|PDB= 2qul |SIZE=350|CAPTION= <scene name='initialview01'>2qul</scene>, resolution 1.79Å | |PDB= 2qul |SIZE=350|CAPTION= <scene name='initialview01'>2qul</scene>, resolution 1.79Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand=MN:MANGANESE (II) ION'>MN</scene> | + | |LIGAND= <scene name='pdbligand=MN:MANGANESE+(II)+ION'>MN</scene> |
|ACTIVITY= | |ACTIVITY= | ||
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY=[[2ou4|2OU4]], [[2qum|2QUM]], [[2qun|2QUN]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2qul FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2qul OCA], [http://www.ebi.ac.uk/pdbsum/2qul PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2qul RCSB]</span> | ||
}} | }} | ||
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[[Category: Yamada, M.]] | [[Category: Yamada, M.]] | ||
[[Category: Yoshida, H.]] | [[Category: Yoshida, H.]] | ||
| - | [[Category: MN]] | ||
[[Category: beta/alpha barrel]] | [[Category: beta/alpha barrel]] | ||
[[Category: isomerase]] | [[Category: isomerase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 04:53:25 2008'' |
Revision as of 01:53, 31 March 2008
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| , resolution 1.79Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | |||||||
| Related: | 2OU4, 2QUM, 2QUN
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal structure of D-tagatose 3-epimerase from Pseudomonas cichorii at 1.79 A resolution
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
2QUL 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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