View source for 6ep6


==ARABIDOPSIS THALIANA GSTU23, reduced==
<StructureSection load='6ep6' size='340' side='right' caption='[[6ep6]], [[Resolution|resolution]] 1.59&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6ep6]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Arath Arath]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6EP6 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6EP6 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[5o84|5o84]]</td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">GSTU23, At1g78320, F3F9.14 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=3702 ARATH])</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Glutathione_transferase Glutathione transferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.5.1.18 2.5.1.18] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6ep6 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6ep6 OCA], [http://pdbe.org/6ep6 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6ep6 RCSB], [http://www.ebi.ac.uk/pdbsum/6ep6 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6ep6 ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/GSTUN_ARATH GSTUN_ARATH]] May be involved in the conjugation of reduced glutathione to a wide number of exogenous and endogenous hydrophobic electrophiles and have a detoxification role against certain herbicides. 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
BACKGROUND: Glutathione transferases play an important role as detoxifying enzymes. In A. thaliana, elevated levels of reactive oxygen species (ROS), provoked during biotic and abiotic stress, influence the activity of GSTU23. The aim of this study is to determine the impact of oxidative stress on the function and structure of GSTU23. METHODS: The impact of oxidation on the function of GSTU23 was studied using a glutathione transferase biochemical assay and mass spectrometry. With kinetics, circular dichroism and thermodynamics, we compared reduced with oxidized GSTU23. X-ray crystal structures of GSTU23 visualize the impacts of oxidation on methionines and cysteines. RESULTS: In the presence of 100muM H2O2, oxidation of the methionine side-chain to a sulfoxide is the prominent post-translational modification, which can be reduced by C. diphtheriae MsrA and MsrB. However, increasing the level to 200muM H2O2 results in a reversible intramolecular disulfide between Cys65-Cys110, which is substrate for glutaredoxin. Under these oxidizing conditions, GSTU23 undergoes a structural change and forms a more favourable enzyme-substrate complex to overcome kcat decrease. CONCLUSIONS AND SIGNIFICANCE: At lower H2O2 levels (100muM), GSTU23 forms methionine sulfoxides. Specifically, oxidation of Met14, located near the catalytic Ser13, could interfere with both GSH binding and catalytic activation. At higher H2O2 levels (200muM), the Cys65-Cys110 disulfide bond protects other cysteines and also methionines from overoxidation. This study shows the impact of oxidative stress on GSTU23 regulated by methionine sulfoxide reductases and glutaredoxin, and the mechanisms involved in maintaining its catalytic functionality under oxidizing conditions.

Disulfide bond formation protects Arabidopsis thaliana glutathione transferase tau 23 from oxidative damage.,Tossounian MA, Van Molle I, Wahni K, Jacques S, Gevaert K, Van Breusegem F, Vertommen D, Young D, Rosado LA, Messens J Biochim Biophys Acta. 2017 Oct 11. pii: S0304-4165(17)30328-8. doi:, 10.1016/j.bbagen.2017.10.007. PMID:29031766<ref>PMID:29031766</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6ep6" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Arath]]
[[Category: Glutathione transferase]]
[[Category: Breusegem, F Van]]
[[Category: Gevaert, K]]
[[Category: Jacques, S]]
[[Category: Messens, J]]
[[Category: Molle, I Van]]
[[Category: Rosado, L]]
[[Category: Tossounian, M A]]
[[Category: Vertommen, D]]
[[Category: Wahni, K]]
[[Category: Young, D]]
[[Category: Peroxidase]]
[[Category: Tau class]]
[[Category: Transferase]]