2R3X

Crystal structure of an R15L hGSTA1-1 mutant complexed with S-hexyl-glutathione

2R3X の概要

• エントリーDOI: 10.2210/pdb2r3x/pdb
• 分子名称: Glutathione S-transferase A1, S-HEXYLGLUTATHIONE (3 entities in total)
• 機能のキーワード: human alpha class glutathione transferase 1-1, s-hexyl glutathione, x-ray crystal structure, transferase
• 由来する生物種: Homo sapiens (human)
• 細胞内の位置: Cytoplasm: P08263
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 52037.15

構造登録者

Burke, J.P.W.G.,Kinsley, N.,Sayed, M.,Sewell, T.,Dirr, H.W. (登録日: 2007-08-30, 公開日: 2007-12-18, 最終更新日: 2023-08-30)

主引用文献

Gildenhuys, S.,Dobreva, M.,Kinsley, N.,Sayed, Y.,Burke, J.,Pelly, S.,Gordon, G.P.,Sayed, M.,Sewell, T.,Dirr, H.W.
Arginine 15 stabilizes an S(N)Ar reaction transition state and the binding of anionic ligands at the active site of human glutathione transferase A1-1.
Biophys.Chem., 146:118-125, 2010

PubMed Abstract: Arg15, conserved in class Alpha GSTs (glutathione transferases), is located at the interface between the G- and H-sites of the active site where its cationic guanidinium group might play a role in catalysis and ligand binding. Arg15 in human GSTA1-1 was replaced with a leucine and crystallographic, spectroscopic, thermodynamic and molecular docking methods were used to investigate the contribution made by Arg15 towards (i) the binding of glutathione (GSH) to the G-site, (ii) the pK(a) of the thiol group of GSH, (iii) the stabilization of an analog of the anionic transition state of the S(N)Ar reaction between 1-chloro-2,4-dinitrobenzene (CDNB) and GSH, and, (iv) the binding of the anionic non-substrate ligand 8-anilino-1-naphthalene sulphonate (ANS) to the H-site. While the R15L mutation substantially diminishes the CDNB-GSH conjugating activity of the enzyme, it has little effect on protein structure and stability. Arg15 does not contribute significantly towards the enzyme's affinity for GSH but does determine the reactivity of GSH by reducing the thiol's pK(a) from 7.6 to 6.6. The anionic sigma-complex formed between GSH and 1,3,5-trinitrobenzene is stabilized by Arg15, suggesting that it also stabilizes the transition state formed in the S(N)Ar reaction between GSH and CDNB. The trinitrocyclohexadienate moiety of the sigma-complex binds the H-site where the catalytic residue, Tyr9, was identified to hydrogen bond to an o-nitro group of the sigma-complex. The affinity for ANS at the H-site is decreased about 3-fold by the R15L mutation implicating the positive electrostatic potential of Arg15 in securing the organic anion at this site.

PubMed: 19959275
DOI: 10.1016/j.bpc.2009.11.003

実験手法

X-RAY DIFFRACTION (1.8 Å)