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Structural understanding of the recycling of oxidized ascorbate by dehydroascorbate reductase (OsDHAR) from Oryza sativa L. japonica

Cited 9 time in scopus
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Title
Structural understanding of the recycling of oxidized ascorbate by dehydroascorbate reductase (OsDHAR) from Oryza sativa L. japonica
Authors
Do, Hackwon
Kim, Il-Sup
Jeon, Byoung Wook
Lee, Chang Woo
Park, Ae Kyung
Wi, Ah Ram
Shin, Seung Chul
Park, Hyun
Kim, Young-Saeng
Yoon, Ho-Sung
Kim, Han-Woo
Lee, Jun Hyuck
Subject
Science & Technology - Other Topics
Keywords
Oryza sativa L. japonica; X-ray crystallography; Ascorbate; Dehydroascorbate reductase
Issue Date
2016
Citation
Do, Hackwon., et al. 2016. Structural understanding of the recycling of oxidized ascorbate by dehydroascorbate reductase (OsDHAR) from Oryza sativa L. japonica. SCIENTIFIC REPORTS, 6(19498): 1-13.
Abstract
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 Å, 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.
DOI
10.1038/srep19498
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