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1u88
From Proteopedia
Crystal Structure Of The 26 Kda Glutathione S-Transferase Y7F mutant From Schistosoma Japonicum Complexed With S-Octyl Glutathione
Overview
Glutathione S-transferases are a family of multifunctional enzymes involved in the metabolism of drugs and xenobiotics. Two tyrosine residues, Tyr 7 and Tyr 111, in the active site of the enzyme play an important role in the binding and catalysis of substrate ligands. The crystal structures of Schistosoma japonicum glutathione S-transferase tyrosine 7 to phenylalanine mutant [SjGST(Y7F)] in complex with the substrate glutathione (GSH) and the competitive inhibitor S-octylglutathione (S-octyl-GSH) have been obtained. These new structural data combined with fluorescence spectroscopy and thermodynamic data, obtained by means of isothermal titration calorimetry, allow for detailed characterization of the ligand-binding process. The binding of S-octyl-GSH to SjGST(Y7F) is enthalpically and entropically driven at temperatures below 30 degrees C. The stoichiometry of the binding is one molecule of S-octyl-GSH per mutant dimer, whereas shorter alkyl derivatives bind with a stoichiometry of two molecules per mutant dimer. The SjGST(Y7F).GSH structure showed no major structural differences compared to the wild-type enzyme. In contrast, the structure of SjGST(Y7F).S-octyl-GSH showed asymmetric binding of S-octyl-GSH. This lack of symmetry is reflected in the lower symmetry space group of the SjGST(Y7F).S-octyl-GSH crystals (P6(3)) compared to that of the SjGST(Y7F).GSH crystals (P6(3)22). Moreover, the binding of S-octyl-GSH to the A subunit is accompanied by conformational changes that may be responsible for the lack of binding to the B subunit.
About this Structure
1U88 is a Single protein structure of sequence from Schistosoma japonicum. Full crystallographic information is available from OCA.
Reference
Crystallographic and thermodynamic analysis of the binding of S-octylglutathione to the Tyr 7 to Phe mutant of glutathione S-transferase from Schistosoma japonicum., Andujar-Sanchez M, Smith AW, Clemente-Jimenez JM, Rodriguez-Vico F, Las Heras-Vazquez FJ, Jara-Perez V, Camara-Artigas A, Biochemistry. 2005 Feb 1;44(4):1174-83. PMID:15667211 Page seeded by OCA on Sat May 3 10:53:09 2008
