title: Conserved residues in the subunit interface of tau glutathione s-transferase affect catalytic and structural functions.
abstract: The tau class glutathione S-transferases (GSTs) have important roles in stress tolerance and the detoxification of herbicides in crops and weeds. Structural investigations of a wheat tau GST (TaGSTU4) show two subunit interactions: a hydrogen bond between the Tyr93 and Pro65 from another subunit of the dimer, and two salt bridges between residues Glu78 and side chains of Arg95 and Arg99 in the opposite subunit. By investigating enzyme activities, kinetic parameters and structural characterizations, this study showed the following results: (i) the hydrogen bond interaction between the Tyr93 and Pro65 was not essential for dimerization, but contributed to the enzyme's catalytic activity, thermal stability and affinity towards substrates glutathione and 1-chloro-2, 4-dinitrobenzene; and (ii) two salt bridges mainly contributed to the protein structure stability and catalysis. The results of this study form a structural and functional basis for rational design of more selective and environmentally friendly herbicides.
authors.affiliation: College of Life Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China.
authors.forename: Cai-Ling
authors.initials: CL
authors.lastname: Wang
authors.forename: Hai-Ling
authors.initials: HL
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D017124:Conserved Sequence; D004795:Enzyme Stability; D005982:Glutathione Transferase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006358:Hot Temperature; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010940:Plant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity; D014908:Triticum / Q000201:enzymology* / Q000235:genetics
chemical_list: D010940:Plant Proteins; D005982:Glutathione Transferase