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< | ==CRYSTAL STRUCTURE OF ESCHERICHIA COLI TRANSALDOLASE B MUTANT E96A== | ||
<StructureSection load='1i2o' size='340' side='right'caption='[[1i2o]], [[Resolution|resolution]] 2.05Å' scene=''> | |||
You may | == Structural highlights == | ||
<table><tr><td colspan='2'>[[1i2o]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1I2O OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1I2O FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.05Å</td></tr> | |||
-- | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1i2o FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1i2o OCA], [https://pdbe.org/1i2o PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1i2o RCSB], [https://www.ebi.ac.uk/pdbsum/1i2o PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1i2o ProSAT]</span></td></tr> | ||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/TALB_ECOLI TALB_ECOLI] Transaldolase is important for the balance of metabolites in the pentose-phosphate pathway.[HAMAP-Rule:MF_00492] | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/i2/1i2o_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1i2o ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The roles of invariant residues at the active site of transaldolase B from Escherichia coli have been probed by site-directed mutagenesis. The mutant enzymes D17A, N35A, E96A, T156A, and S176A were purified from a talB-deficient host and analyzed with respect to their 3D structure and kinetic behavior. X-ray analysis showed that side chain replacement did not induce unanticipated structural changes in the mutant enzymes. Three mutations, N35A, E96A, and T156A resulted mainly in an effect on apparent kcat, with little changes in apparent Km values for the substrates. Residues N35 and T156 are involved in the positioning of a catalytic water molecule at the active site and the side chain of E96 participates in concert with this water molecule in proton transfer during catalysis. Substitution of Ser176 by alanine resulted in a mutant enzyme with 2.5% residual activity. The apparent Km value for the donor substrate, fructose 6-phosphate, was increased nearly fivefold while the apparent Km value for the acceptor substrate, erythrose 4-phosphate remained unchanged, consistent with a function for S176 in the binding of the C1 hydroxyl group of the donor substrate. The mutant D17A showed a 300-fold decrease in kcat, and a fivefold increase in the apparent Km value for the acceptor substrate erythrose 4-phosphate, suggesting a role of this residue in carbon-carbon bond cleavage and stabilization of the carbanion/enamine intermediate. | |||
Identification of catalytically important residues in the active site of Escherichia coli transaldolase.,Schorken U, Thorell S, Schurmann M, Jia J, Sprenger GA, Schneider G Eur J Biochem. 2001 Apr;268(8):2408-15. PMID:11298760<ref>PMID:11298760</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1i2o" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Transaldolase 3D structures|Transaldolase 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
== | |||
== | |||
< | |||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Jia | [[Category: Jia J]] | ||
[[Category: Schneider | [[Category: Schneider G]] | ||
[[Category: Thorell | [[Category: Thorell S]] | ||
Latest revision as of 09:20, 9 August 2023
CRYSTAL STRUCTURE OF ESCHERICHIA COLI TRANSALDOLASE B MUTANT E96ACRYSTAL STRUCTURE OF ESCHERICHIA COLI TRANSALDOLASE B MUTANT E96A
Structural highlights
FunctionTALB_ECOLI Transaldolase is important for the balance of metabolites in the pentose-phosphate pathway.[HAMAP-Rule:MF_00492] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe roles of invariant residues at the active site of transaldolase B from Escherichia coli have been probed by site-directed mutagenesis. The mutant enzymes D17A, N35A, E96A, T156A, and S176A were purified from a talB-deficient host and analyzed with respect to their 3D structure and kinetic behavior. X-ray analysis showed that side chain replacement did not induce unanticipated structural changes in the mutant enzymes. Three mutations, N35A, E96A, and T156A resulted mainly in an effect on apparent kcat, with little changes in apparent Km values for the substrates. Residues N35 and T156 are involved in the positioning of a catalytic water molecule at the active site and the side chain of E96 participates in concert with this water molecule in proton transfer during catalysis. Substitution of Ser176 by alanine resulted in a mutant enzyme with 2.5% residual activity. The apparent Km value for the donor substrate, fructose 6-phosphate, was increased nearly fivefold while the apparent Km value for the acceptor substrate, erythrose 4-phosphate remained unchanged, consistent with a function for S176 in the binding of the C1 hydroxyl group of the donor substrate. The mutant D17A showed a 300-fold decrease in kcat, and a fivefold increase in the apparent Km value for the acceptor substrate erythrose 4-phosphate, suggesting a role of this residue in carbon-carbon bond cleavage and stabilization of the carbanion/enamine intermediate. Identification of catalytically important residues in the active site of Escherichia coli transaldolase.,Schorken U, Thorell S, Schurmann M, Jia J, Sprenger GA, Schneider G Eur J Biochem. 2001 Apr;268(8):2408-15. PMID:11298760[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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