GST_N family, Class Zeta subfamily; GSTs are cytosolic dimeric proteins involved in cellular detoxification by catalyzing the conjugation of glutathione (GSH) with a wide range of endogenous and xenobiotic alkylating agents, including carcinogens, therapeutic drugs, environmental toxins and products of oxidative stress. The GST fold contains an N-terminal TRX-fold domain and a C-terminal alpha helical domain, with an active site located in a cleft between the two domains. Class Zeta GSTs, also known as maleylacetoacetate (MAA) isomerases, catalyze the isomerization of MAA to fumarylacetoacetate, the penultimate step in tyrosine/phenylalanine catabolism, using GSH as a cofactor. They show little GSH-conjugating activity towards traditional GST substrates but display modest GSH peroxidase activity. They are also implicated in the detoxification of the carcinogen dichloroacetic acid by catalyzing its dechlorination to glyoxylic acid.
Feature 1:GSH binding site (G-site) [chemical binding site]
Evidence:
Structure:1FW1; Human Class Zeta GST with bound GSH; contacts at 3.5A - View structure with Cn3D
Comment:The GST active site is composed of a GSH binding site (G-site), common to all GSTs, and a xenobiotic binding site (H-site), which varies between different classes and isotypes. Residues from the N-terminal TRX-fold domain form the G-site while the H-site is comprised mainly of residues from the C-terminal alpha helical domain.
Comment:The N-terminal serine may play an important role in activating the thiol group of GSH by stabilizing its thiolate anion form.
Jiyao W et al.(2023). "The conserved domain database in 2023.",