1.3-A resolution structure of human glutathione S-transferase with S-hexyl glutathione bound reveals possible extended ligandin binding site.


Journal Article

Cytosolic glutathione S-transferases (GSTs) play a critical role in xenobiotic binding and metabolism, as well as in modulation of oxidative stress. Here, the high-resolution X-ray crystal structures of homodimeric human GSTA1-1 in the apo form and in complex with S-hexyl glutathione (two data sets) are reported at 1.8, 1.5, and 1.3A respectively. At this level of resolution, distinct conformations of the alkyl chain of S-hexyl glutathione are observed, reflecting the nonspecific nature of the hydrophobic substrate binding site (H-site). Also, an extensive network of ordered water, including 75 discrete solvent molecules, traverses the open subunit-subunit interface and connects the glutathione binding sites in each subunit. In the highest-resolution structure, three glycerol moieties lie within this network and directly connect the amino termini of the glutathione molecules. A search for ligand binding sites with the docking program Molecular Operating Environment identified the ordered water network binding site, lined mainly with hydrophobic residues, suggesting an extended ligand binding surface for nonsubstrate ligands, the so-called ligandin site. Finally, detailed comparison of the structures reported here with previously published X-ray structures reveal a possible reaction coordinate for ligand-dependent conformational changes in the active site and the C-terminus.

Full Text

Cited Authors

  • Le Trong, I; Stenkamp, RE; Ibarra, C; Atkins, WM; Adman, ET

Published Date

  • September 2002

Published In

Volume / Issue

  • 48 / 4

Start / End Page

  • 618 - 627

PubMed ID

  • 12211029

Pubmed Central ID

  • 12211029

Electronic International Standard Serial Number (EISSN)

  • 1097-0134

International Standard Serial Number (ISSN)

  • 0887-3585

Digital Object Identifier (DOI)

  • 10.1002/prot.10162


  • eng