Catalytically active monomer of glutathione S-transferase pi and key residues involved in the electrostatic interaction between subunits.

ABSTRACT: Human glutathione transferase pi (GST pi) has been crystallized as a homodimer, with a subunit molecular mass of approximately 23 kDa; however, in solution the average molecular mass depends on protein concentration, approaching that of monomer at <0.03 mg/ml, concentrations typically used to measure catalytic activity of the enzyme. Electrostatic interaction at the subunit interface greatly influences the dimer-monomer equilibrium of the enzyme and is an important force for holding subunits together. Arg-70, Arg-74, Asp-90, Asp-94, and Thr-67 were selected as target sites for mutagenesis, because they are at the subunit interface. R70Q, R74Q, D90N, D94N, and T67A mutant enzymes were constructed, expressed in Escherichia coli, and purified. The construct of N-terminal His tag enzyme facili

SUBMITTER: Huang YC 

PROVIDER: S-EPMC2583305 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature