Glutathione S-transferases (GSTs) are a family of phase II detoxification enzymes whose main function is to improve plant resistance to stresses. To understand the structural effects of tau class GSTs on their function, using OsGSTU17 as an example, we predicted three pairs of residues involving in the interactions between its domains and linker region, and obtained the corresponding single mutation sequences through site-directed mutating Arg20, Glu74 and Asp77 which involved the hydrogen bonds and salt bridges between domains.