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| | ==Dehydroascorbate reductase (OsDHAR) complexed with ASA== | | ==Dehydroascorbate reductase (OsDHAR) complexed with ASA== |
| - | <StructureSection load='5d9w' size='340' side='right' caption='[[5d9w]], [[Resolution|resolution]] 1.69Å' scene=''> | + | <StructureSection load='5d9w' size='340' side='right'caption='[[5d9w]], [[Resolution|resolution]] 1.69Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[5d9w]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5D9W OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5D9W FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[5d9w]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Oryza_sativa_Japonica_Group Oryza sativa Japonica Group]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5D9W OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5D9W FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ASC:ASCORBIC+ACID'>ASC</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.6897Å</td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[5d9t|5d9t]], [[5d9v|5d9v]], [[5d9x|5d9x]]</td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ASC:ASCORBIC+ACID'>ASC</scene></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=5d9w FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5d9w OCA], [http://pdbe.org/5d9w PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5d9w RCSB], [http://www.ebi.ac.uk/pdbsum/5d9w PDBsum]</span></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=5d9w FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5d9w OCA], [https://pdbe.org/5d9w PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5d9w RCSB], [https://www.ebi.ac.uk/pdbsum/5d9w PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5d9w ProSAT]</span></td></tr> |
| | </table> | | </table> |
| - | <div style="background-color:#fffaf0;">
| + | == Function == |
| - | == Publication Abstract from PubMed == | + | [https://www.uniprot.org/uniprot/DHAR1_ORYSJ DHAR1_ORYSJ] Involved in ascorbate homeostasis. Maintains redox pools of ascorbate by recycling dihydroascorbate (DHA) to ascorbate (Probable). Involved in scavenging reactive oxygen species (ROS) under oxidative stresses. Possesses dehydroascorbate reductase (DHAR) activity in vitro (PubMed:19011360). May function via a ping-pong reaction mechanism with an electron transfer at the active site (PubMed:26775680). Possesses chaperone-like activity in vitro (PubMed:26775680).<ref>PMID:19011360</ref> <ref>PMID:26775680</ref> <ref>PMID:23519921</ref> |
| - | Dehydroascorbate reductase (DHAR) is a key enzyme involved in the recycling of ascorbate, which catalyses the glutathione (GSH)-dependent reduction of oxidized ascorbate (dehydroascorbate, DHA). As a result, DHAR regenerates a pool of reduced ascorbate and detoxifies reactive oxygen species (ROS). In previous experiments involving transgenic rice, we observed that overexpression of DHAR enhanced grain yield and biomass. Since the structure of DHAR is not available, the enzymatic mechanism is not well-understood and remains poorly characterized. To elucidate the molecular basis of DHAR catalysis, we determined the crystal structures of DHAR from Oryza sativa L. japonica (OsDHAR) in the native, ascorbate-bound, and GSH-bound forms and refined their resolutions to 1.9, 1.7, and 1.7 A, respectively. These complex structures provide the first information regarding the location of the ascorbate and GSH binding sites and their interacting residues. The location of the ascorbate-binding site overlaps with the GSH-binding site, suggesting a ping-pong kinetic mechanism for electron transfer at the common Cys20 active site. Our structural information and mutagenesis data provide useful insights into the reaction mechanism of OsDHAR against ROS-induced oxidative stress in rice.
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| - | Structural understanding of the recycling of oxidized ascorbate by dehydroascorbate reductase (OsDHAR) from Oryza sativa L. japonica.,Do H, Kim IS, Jeon BW, Lee CW, Park AK, Wi AR, Shin SC, Park H, Kim YS, Yoon HS, Kim HW, Lee JH Sci Rep. 2016 Jan 18;6:19498. doi: 10.1038/srep19498. PMID:26775680<ref>PMID:26775680</ref>
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| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
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| - | </div> | + | |
| - | <div class="pdbe-citations 5d9w" style="background-color:#fffaf0;"></div> | + | |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Do, H]] | + | [[Category: Large Structures]] |
| - | [[Category: Lee, J H]]
| + | [[Category: Oryza sativa Japonica Group]] |
| - | [[Category: Ascorbate]]
| + | [[Category: Do H]] |
| - | [[Category: Oryza sativa l. japonica]] | + | [[Category: Lee JH]] |
| - | [[Category: Osdhar]] | + | |
| - | [[Category: Plant protein]] | + | |
| Structural highlights
Function
DHAR1_ORYSJ Involved in ascorbate homeostasis. Maintains redox pools of ascorbate by recycling dihydroascorbate (DHA) to ascorbate (Probable). Involved in scavenging reactive oxygen species (ROS) under oxidative stresses. Possesses dehydroascorbate reductase (DHAR) activity in vitro (PubMed:19011360). May function via a ping-pong reaction mechanism with an electron transfer at the active site (PubMed:26775680). Possesses chaperone-like activity in vitro (PubMed:26775680).[1] [2] [3]
References
- ↑ Shin SY, Kim IS, Kim YH, Park HM, Lee JY, Kang HG, Yoon HS. Scavenging reactive oxygen species by rice dehydroascorbate reductase alleviates oxidative stresses in Escherichia coli. Mol Cells. 2008 Dec 31;26(6):616-20 PMID:19011360
- ↑ Do H, Kim IS, Jeon BW, Lee CW, Park AK, Wi AR, Shin SC, Park H, Kim YS, Yoon HS, Kim HW, Lee JH. Structural understanding of the recycling of oxidized ascorbate by dehydroascorbate reductase (OsDHAR) from Oryza sativa L. japonica. Sci Rep. 2016 Jan 18;6:19498. doi: 10.1038/srep19498. PMID:26775680 doi:http://dx.doi.org/10.1038/srep19498
- ↑ Kim YS, Kim IS, Bae MJ, Choe YH, Kim YH, Park HM, Kang HG, Yoon HS. Homologous expression of cytosolic dehydroascorbate reductase increases grain yield and biomass under paddy field conditions in transgenic rice (Oryza sativa L. japonica). Planta. 2013 Jun;237(6):1613-25. PMID:23519921 doi:10.1007/s00425-013-1862-8
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