Oakley A J, Lo Bello M, Battistoni A, Ricci G, Rossjohn J, Villar H O, Parker M W
The Ian Potter Foundation Protein Crystallography Laboratory, St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.
J Mol Biol. 1997 Nov 21;274(1):84-100. doi: 10.1006/jmbi.1997.1364.
The human pi-class glutathione S-transferase (hGST P1-1) is a target for structure-based inhibitor design with the aim of developing drugs that could be used as adjuvants in chemotherapeutic treatment. Here we present seven crystal structures of the enzyme in complex with substrate (glutathione) and two inhibitors (S-hexyl glutathione and gamma-glutamyl- (S-benzyl)cysteinyl-D-phenylglycine). The binding of the modified glutathione inhibitor, gamma-glutamyl-(S-benzyl)cysteinyl-D-phenylglycine, has been characterized with the phenyl group stacking against the benzyl moiety of the inhibitor and making interactions with the active-site residues Phe8 and Trp38. The structure provides an explanation as to why this compound inhibits the pi-class GST much better than the other GST classes. The structure of the enzyme in complex with glutathione has been determined to high resolution (1.9 to 2.2 A) in three different crystal forms and at two different temperatures (100 and 288 K). In one crystal form, the direct hydrogen-bonding interaction between the hydroxyl group of Tyr7, a residue involved in catalysis, and the thiol group of the substrate, glutathione, is broken and replaced by a water molecule that mediates the interaction. The hydrogen-bonding partner of the hydroxyl group of Tyr108, another residue implicated in the catalysis, is space-group dependent. A high-resolution (2.0 A) structure of the enzyme in complex with S-hexyl glutathione in a new crystal form is presented. The enzyme-inhibitor complexes show that the binding of ligand into the electrophilic binding site does not lead to any conformational changes of the protein.
人π类谷胱甘肽S-转移酶（hGST P1-1）是基于结构的抑制剂设计的靶点，目的是开发可作为化疗辅助药物的药物。在此，我们展示了该酶与底物（谷胱甘肽）和两种抑制剂（S-己基谷胱甘肽和γ-谷氨酰-（S-苄基）半胱氨酰-D-苯甘氨酸）形成复合物的七种晶体结构。修饰后的谷胱甘肽抑制剂γ-谷氨酰-（S-苄基）半胱氨酰-D-苯甘氨酸的结合特征为，苯基与抑制剂的苄基部分堆积，并与活性位点残基苯丙氨酸8和色氨酸38相互作用。该结构解释了为什么这种化合物比其他类谷胱甘肽S-转移酶能更好地抑制π类谷胱甘肽S-转移酶。已在三种不同晶体形式和两个不同温度（100和288 K）下，以高分辨率（1.9至2.2 Å）测定了该酶与谷胱甘肽形成复合物的结构。在一种晶体形式中，参与催化的残基酪氨酸7的羟基与底物谷胱甘肽的硫醇基团之间的直接氢键相互作用被破坏，并被一个介导相互作用的水分子取代。另一个参与催化的残基酪氨酸108的羟基的氢键伙伴取决于空间群。展示了该酶与S-己基谷胱甘肽在一种新晶体形式下形成复合物的高分辨率（2.0 Å）结构。酶-抑制剂复合物表明，配体结合到亲电结合位点不会导致蛋白质发生任何构象变化。
