The three-dimensional structure of a class-Pi glutathione S-transferase complexed with glutathione: the active-site hydration provides insights into the reaction mechanism

Abstract

The structure of mouse liver glutathione S-transferase P1-1 complexed with its substrate glutathione (GSH) has been determined by X-ray diffraction analysis. No conformational changes in the glutathione moiety or in the protein, other than small adjustments of some side chains, are observed when compared with glutathione adduct complexes. Our structure confirms that the role of Tyr-7 is to stabilize the thiolate by hydrogen bonding and to position it in the right orientation. A comparison of the enzyme-GSH structure reported here with previously described structures reveals rearrangements in a well-defined network of water molecules in the active site. One of these water molecules (W0), identified in the unliganded enzyme (carboxymethylated at Cys-47), is displaced by the binding of GSH, and a further water molecule (W4) is displaced following the binding of the electrophilic substrate and the formation of the glutathione conjugate. The possibility that one of these water molecules participates in the proton abstraction from the glutathione thiol is discussed.

Catalytically Active Monomer of Glutathione S-Transferase π and Key Residues Involved in the Electrostatic Interaction between Subunits

“…Tyr-7, which is conserved in all cytosolic GSTs, is an essential residue for catalytic activity (41,42). The structure of mouse GST confirms that the role of Tyr-7 is to stabilize the thiolate by hydrogen bonding and to position it in the right orientation (40). Asp-98, an evolutionally conserved aspartyl residue across the dimer interface, participates in GSH recognition (7,11,43).…”

“…The highly specific G-site for binding GSH is formed by Tyr-7, Arg-13, Trp-38, Lys-44, Gln-51, Leu-52, and Ser-65 from one subunit and Asp-98 from the other subunit (7,10,11,40,41). Tyr-7, which is conserved in all cytosolic GSTs, is an essential residue for catalytic activity (41,42).…”

Glutathione‐S‐transferase enhances proliferation‐migration and protects against shikonin‐induced cell death in breast cancer cells

“…Dimeric shikonin and three-dimensional structure of p-GST had been determined by nuclear magnetic resonance spectroscopy [30] and crystallography [31]; our shikonin-GST binding assays suggested that a homology dimer GST might bind with 20 monomeric or 10 dimeric shikonins.…”

Structural modeling and simulation studies of Brugia malayi glutathione-S-transferase with compounds exhibiting antifilarial activity: Implications in drug targeting and designing

“…2B). The domains I and II form G-site (GSH binding site) and H-site (xenobiotic binding site), respectively [28] specifically for detoxification purpose. The arrangement of a/b in both domains in such a manner reflects the structural conservation between species which might be due to the execution of similar functions The overall frequency of different structural patterns detected in BmGST by PyMOL 1.0 [29] were 54.8% helix, 9.6% sheet, 13% turn, 19.2% coil and 3.4% 3-10 helix which is in accordance with an earlier report [30].…”