4ccq: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
==Crystal structure of the thioredoxin reductase from Entamoeba histolytica with NADP== | ==Crystal structure of the thioredoxin reductase from Entamoeba histolytica with NADP== | ||
<StructureSection load='4ccq' size='340' side='right' caption='[[4ccq]], [[Resolution|resolution]] 1.50Å' scene=''> | <StructureSection load='4ccq' size='340' side='right' caption='[[4ccq]], [[Resolution|resolution]] 1.50Å' scene=''> | ||
| Line 6: | Line 7: | ||
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4ccr|4ccr]]</td></tr> | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4ccr|4ccr]]</td></tr> | ||
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Thioredoxin-disulfide_reductase Thioredoxin-disulfide reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.8.1.9 1.8.1.9] </span></td></tr> | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Thioredoxin-disulfide_reductase Thioredoxin-disulfide reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.8.1.9 1.8.1.9] </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=4ccq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ccq OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4ccq RCSB], [http://www.ebi.ac.uk/pdbsum/4ccq PDBsum]</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=4ccq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ccq OCA], [http://pdbe.org/4ccq PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4ccq RCSB], [http://www.ebi.ac.uk/pdbsum/4ccq PDBsum]</span></td></tr> | ||
</table> | </table> | ||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The anti-arthritic gold-containing drug Auranofin is lethal to the protozoan intestinal parasite Entamoeba histolytica, the causative agent of human amebiasis, in both culture and animal models of the disease. A putative mechanism of Auranofin action proposes that monovalent gold, Au(I), released from the drug, can bind to the redox-active dithiol group of thioredoxin reductase (TrxR). Au(I) binding in the active site is expected to prevent electron transfer to the downstream substrate thioredoxin (Trx), thus interfering with redox homeostasis in the parasite. To clarify the molecular mechanism of Auranofin action in more detail, we determined a series of atomic resolution x-ray structures for E. histolytica thioredoxin (EhTrx) and thioredoxin reductase (EhTrxR), the latter with and without Auranofin. Only the disulfide-bonded form of the active site dithiol (Cys140-Cys143) was invariably observed in crystals of EhTrxR in spite of the addition of reductants in various crystallization trials, and no gold was found associated with these cysteines. Non-catalytic Cys286 was identified as the only site of modification, but further mutagenesis studies using the C286Q mutant demonstrated that this site was not responsible for inhibition of EhTrxR by Auranofin. Interestingly, we obtained both of the catalytically-relevant conformations of this bacterial-like, low molecular weight TrxR in crystals without requiring an engineered disulfide linkage between Cys mutants of TrxR and Trx (as was originally done with E. coli TrxR and Trx). We note that the -CXXC- catalytic motif, even if reduced, would likely not provide space sufficient to bind Au(I) by both cysteines of the dithiol group. | |||
X-ray structures of thioredoxin and thioredoxin reductase from Entamoeba histolytica and prevailing hypothesis of the mechanism of Auranofin action.,Parsonage D, Sheng F, Hirata K, Debnath A, McKerrow JH, Reed SL, Abagyan R, Poole LB, Podust LM J Struct Biol. 2016 Feb 11. pii: S1047-8477(16)30030-2. doi:, 10.1016/j.jsb.2016.02.015. PMID:26876147<ref>PMID:26876147</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 4ccq" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
Revision as of 13:17, 26 February 2016
Crystal structure of the thioredoxin reductase from Entamoeba histolytica with NADPCrystal structure of the thioredoxin reductase from Entamoeba histolytica with NADP
Structural highlights
Publication Abstract from PubMedThe anti-arthritic gold-containing drug Auranofin is lethal to the protozoan intestinal parasite Entamoeba histolytica, the causative agent of human amebiasis, in both culture and animal models of the disease. A putative mechanism of Auranofin action proposes that monovalent gold, Au(I), released from the drug, can bind to the redox-active dithiol group of thioredoxin reductase (TrxR). Au(I) binding in the active site is expected to prevent electron transfer to the downstream substrate thioredoxin (Trx), thus interfering with redox homeostasis in the parasite. To clarify the molecular mechanism of Auranofin action in more detail, we determined a series of atomic resolution x-ray structures for E. histolytica thioredoxin (EhTrx) and thioredoxin reductase (EhTrxR), the latter with and without Auranofin. Only the disulfide-bonded form of the active site dithiol (Cys140-Cys143) was invariably observed in crystals of EhTrxR in spite of the addition of reductants in various crystallization trials, and no gold was found associated with these cysteines. Non-catalytic Cys286 was identified as the only site of modification, but further mutagenesis studies using the C286Q mutant demonstrated that this site was not responsible for inhibition of EhTrxR by Auranofin. Interestingly, we obtained both of the catalytically-relevant conformations of this bacterial-like, low molecular weight TrxR in crystals without requiring an engineered disulfide linkage between Cys mutants of TrxR and Trx (as was originally done with E. coli TrxR and Trx). We note that the -CXXC- catalytic motif, even if reduced, would likely not provide space sufficient to bind Au(I) by both cysteines of the dithiol group. X-ray structures of thioredoxin and thioredoxin reductase from Entamoeba histolytica and prevailing hypothesis of the mechanism of Auranofin action.,Parsonage D, Sheng F, Hirata K, Debnath A, McKerrow JH, Reed SL, Abagyan R, Poole LB, Podust LM J Struct Biol. 2016 Feb 11. pii: S1047-8477(16)30030-2. doi:, 10.1016/j.jsb.2016.02.015. PMID:26876147[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
|
| ||||||||||||||||||||