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Structure and catalytic mechanism of monodehydroascorbate reductase, MDHAR, from Oryza sativa L. japonica

Cited 28 time in wos
Cited 33 time in scopus

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dc.contributor.authorPark, Ae Kyung-
dc.contributor.authorKim, Il-Sup-
dc.contributor.authorDo, Hackwon-
dc.contributor.authorJeon, Byoung Wook-
dc.contributor.authorLee, Chang Woo-
dc.contributor.authorRoh, Soo Jung-
dc.contributor.authorShin, Seung Chul-
dc.contributor.authorPark, Hyun-
dc.contributor.authorKim, Young-Saeng-
dc.contributor.authorKim, Yul-Ho-
dc.contributor.authorYoon, Ho-Sung-
dc.contributor.authorLee, Jun Hyuck-
dc.contributor.authorKim, Han-Woo-
dc.date.accessioned2017-08-03T13:40:19Z-
dc.date.available2017-08-03T13:40:19Z-
dc.date.issued2016-
dc.description.abstractAscorbic acid (AsA) maintains redox homeostasis by scavenging reactive oxygen species from prokaryotes to eukaryotes, especially plants. The enzyme monodehydroascorbate reductase (MDHAR) regenerates AsA by catalysing the reduction of monodehydroascorbate, using NADH or NADPH as an electron donor. The detailed recycling mechanism of MDHAR remains unclear due to lack of structural information. Here, we present the crystal structures of MDHAR in the presence of cofactors, nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP+), and complexed with AsA as well as its analogue, isoascorbic acid (ISD). The overall structure of MDHAR is similar to other iron-sulphur protein reductases, except for a unique long loop of 63?80 residues, which seems to be essential in forming the active site pocket. From the structural analysis and structure-guided point mutations, we found that the Arg320 residue plays a major substrate binding role, and the Tyr349 residue mediates electron transfer from NAD(P)H to bound substrate via FAD. The enzymatic activity of MDHAR favours NADH as an electron donor over NADPH. Our results show, for the first time, structural insights into this preference. The MDHAR-ISD complex structure revealed an alternative binding conformation of ISD, compared with the MDHAR-AsA complex. This implies a broad substrate (antioxidant) specificity and resulting greater protective ability of MDHAR.-
dc.languageEnglish-
dc.subjectScience & Technology - Other Topics-
dc.titleStructure and catalytic mechanism of monodehydroascorbate reductase, MDHAR, from Oryza sativa L. japonica-
dc.typeArticle-
dc.identifier.bibliographicCitationPark, Ae Kyung, et al. 2016. "Structure and catalytic mechanism of monodehydroascorbate reductase, MDHAR, from Oryza sativa L. japonica". <em>Scientific Reports,</em>, 6(33903): 1-10.-
dc.citation.titleScientific Reports,-
dc.citation.volume6-
dc.citation.number33903-
dc.citation.page1-10.-
dc.identifier.doi10.1038/srep33903-
dc.subject.keywordCrystal structure-
dc.subject.keywordIsoascorbic acid-
dc.subject.keywordMonodehydroascorbate reductase-
dc.subject.keywordReactive oxygen species-
dc.identifier.scopusid2-s2.0-84988643225-
dc.identifier.wosid000383695100001-
Appears in Collections  
2014-2016, Antarctic Organisms: Cold-Adaptation Mechanism and Its Application (14-16) / Park; Hyun (PE14070; PE15070; PE16070)
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