| Structural highlights
Function
[GSTO1_HUMAN] Exhibits glutathione-dependent thiol transferase and dehydroascorbate reductase activities. Has S-(phenacyl)glutathione reductase activity. Has also glutathione S-transferase activity. Participates in the biotransformation of inorganic arsenic and reduces monomethylarsonic acid (MMA) and dimethylarsonic acid.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
The polymorphic deletion of Glu-155 from human glutathione transferase omega1 (GSTO1-1) occurs in most populations. Although the recombinant DeltaGlu-155 enzyme expressed in Escherichia coli is active, the deletion causes a deficiency of the active enzyme in vivo. The crystal structure and the folding/unfolding kinetics of the DeltaGlu-155 variant were determined in order to investigate the cause of the rapid loss of the enzyme in human cells. The crystal structure revealed altered packing around the Glu-155 deletion, an increase in the predicted solvent-accessible area and a corresponding reduction in the buried surface area. This increase in solvent accessibility was consistent with an elevated Stern-Volmer constant. The unfolding of both the wild type and DeltaGlu-155 enzyme in urea is best described by a three-state model, and there is evidence for the more pronounced population of an intermediate state by the DeltaGlu-155 enzymes. Studies using intrinsic fluorescence revealed a free energy change around 14.4 kcal/mol for the wild type compared with around 8.6 kcal/mol for the DeltaGlu-155 variant, which indicates a decrease in stability associated with the Glu-155 deletion. Urea induced unfolding of the wild type GSTO1-1 was reversible through an initial fast phase followed by a second slow phase. In contrast, the DeltaGlu-155 variant lacks the slow phase, indicating a refolding defect. It is possible that in some conditions in vivo, the increased solvent-accessible area and the low stability of the DeltaGlu-155 variant may promote its unfolding, whereas the refolding defect limits its refolding, resulting in GSTO1-1 deficiency.
Novel folding and stability defects cause a deficiency of human glutathione transferase omega 1.,Zhou H, Brock J, Casarotto MG, Oakley AJ, Board PG J Biol Chem. 2011 Feb 11;286(6):4271-9. Epub 2010 Nov 24. PMID:21106529[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Board PG, Coggan M, Chelvanayagam G, Easteal S, Jermiin LS, Schulte GK, Danley DE, Hoth LR, Griffor MC, Kamath AV, Rosner MH, Chrunyk BA, Perregaux DE, Gabel CA, Geoghegan KF, Pandit J. Identification, characterization, and crystal structure of the Omega class glutathione transferases. J Biol Chem. 2000 Aug 11;275(32):24798-806. PMID:10783391 doi:10.1074/jbc.M001706200
- ↑ Zakharyan RA, Sampayo-Reyes A, Healy SM, Tsaprailis G, Board PG, Liebler DC, Aposhian HV. Human monomethylarsonic acid (MMA(V)) reductase is a member of the glutathione-S-transferase superfamily. Chem Res Toxicol. 2001 Aug;14(8):1051-7. PMID:11511179
- ↑ Board PG, Anders MW. Glutathione transferase omega 1 catalyzes the reduction of S-(phenacyl)glutathiones to acetophenones. Chem Res Toxicol. 2007 Jan;20(1):149-54. PMID:17226937 doi:10.1021/tx600305y
- ↑ Board PG, Coggan M, Cappello J, Zhou H, Oakley AJ, Anders MW. S-(4-Nitrophenacyl)glutathione is a specific substrate for glutathione transferase omega 1-1. Anal Biochem. 2008 Mar 1;374(1):25-30. Epub 2007 Sep 29. PMID:18028863 doi:10.1016/j.ab.2007.09.029
- ↑ Zhou H, Brock J, Casarotto MG, Oakley AJ, Board PG. Novel folding and stability defects cause a deficiency of human glutathione transferase omega 1. J Biol Chem. 2011 Feb 11;286(6):4271-9. Epub 2010 Nov 24. PMID:21106529 doi:10.1074/jbc.M110.197822
- ↑ Zhou H, Brock J, Casarotto MG, Oakley AJ, Board PG. Novel folding and stability defects cause a deficiency of human glutathione transferase omega 1. J Biol Chem. 2011 Feb 11;286(6):4271-9. Epub 2010 Nov 24. PMID:21106529 doi:10.1074/jbc.M110.197822
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