Structural Insights into the Dehydroascorbate Reductase Activity of Human Omega-Class Glutathione Transferases
dc.contributor.author | Zhou, Huina | |
dc.contributor.author | Brock, Joseph | |
dc.contributor.author | Liu, Dan | |
dc.contributor.author | Board, Philip | |
dc.contributor.author | Oakley, Aaron | |
dc.date.accessioned | 2015-12-10T22:28:44Z | |
dc.date.issued | 2012 | |
dc.date.updated | 2016-02-24T10:27:49Z | |
dc.description.abstract | The reduction of dehydroascorbate (DHA) to ascorbic acid (AA) is a vital cellular function. The omega-class glutathione transferases (GSTs) catalyze several reductive reactions in cellular biochemistry, including DHA reduction. In humans, two isozymes (GSTO1-1 and GSTO2-2) with significant DHA reductase (DHAR) activity are found, sharing 64% sequence identity. While the activity of GSTO2-2 is higher, it is significantly more unstable in vitro. We report the first crystal structures of human GSTO2-2, stabilized through site-directed mutagenesis and determined at 1.9 Å resolution in the presence and absence of glutathione (GSH). The structure of a human GSTO1-1 has been determined at 1.7 Å resolution in complex with the reaction product AA, which unexpectedly binds in the G-site, where the glutamyl moiety of GSH binds. The structure suggests a similar mode of ascorbate binding in GSTO2-2. This is the first time that a non-GSH-based reaction product has been observed in the G-site of any GST. AA stacks against a conserved aromatic residue, F34 (equivalent to Y34 in GSTO2-2). Mutation of Y34 to alanine in GSTO2-2 eliminates DHAR activity. From these structures and other biochemical data, we propose a mechanism of substrate binding and catalysis of DHAR activity. Crown | |
dc.identifier.issn | 0022-2836 | |
dc.identifier.uri | http://hdl.handle.net/1885/54590 | |
dc.publisher | Elsevier | |
dc.source | Journal of Molecular Biology | |
dc.subject | Keywords: adrenochrome; alanine; ascorbic acid; dehydroascorbic acid reductase; glutathione; glutathione transferase; omega class glutathione transferase; unclassified drug; article; binding site; controlled study; crystal structure; enzyme active site; enzyme acti ascorbic acid; enzyme mechanism; induced fit; reduction; structure | |
dc.title | Structural Insights into the Dehydroascorbate Reductase Activity of Human Omega-Class Glutathione Transferases | |
dc.type | Journal article | |
local.bibliographicCitation.issue | 3 | |
local.bibliographicCitation.lastpage | 203 | |
local.bibliographicCitation.startpage | 190 | |
local.contributor.affiliation | Zhou, Huina, College of Medicine, Biology and Environment, ANU | |
local.contributor.affiliation | Brock, Joseph, College of Physical and Mathematical Sciences, ANU | |
local.contributor.affiliation | Liu, Dan, College of Medicine, Biology and Environment, ANU | |
local.contributor.affiliation | Board, Philip, College of Medicine, Biology and Environment, ANU | |
local.contributor.affiliation | Oakley, Aaron, College of Physical and Mathematical Sciences, ANU | |
local.contributor.authoremail | u4245938@anu.edu.au | |
local.contributor.authoruid | Zhou, Huina, u4426159 | |
local.contributor.authoruid | Brock, Joseph, u2553446 | |
local.contributor.authoruid | Liu, Dan, u4245938 | |
local.contributor.authoruid | Board, Philip, u7701651 | |
local.contributor.authoruid | Oakley, Aaron, u4134401 | |
local.description.embargo | 2037-12-31 | |
local.description.notes | Imported from ARIES | |
local.identifier.absfor | 060112 - Structural Biology (incl. Macromolecular Modelling) | |
local.identifier.absseo | 970106 - Expanding Knowledge in the Biological Sciences | |
local.identifier.ariespublication | u4020362xPUB305 | |
local.identifier.citationvolume | 420 | |
local.identifier.doi | 10.1016/j.jmb.2012.04.014 | |
local.identifier.scopusID | 2-s2.0-84862022469 | |
local.identifier.thomsonID | 000305873700006 | |
local.identifier.uidSubmittedBy | u4020362 | |
local.type.status | Published Version |
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