GST_N family, Class Alpha 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. The class Alpha subfamily is composed of eukaryotic GSTs which can form homodimer and heterodimers. There are at least six types of class Alpha GST subunits in rats, four of which have human counterparts, resulting in many possible isoenzymes with different activities, tissue distribution and substrate specificities. Human GSTA1-1 and GSTA2-2 show high GSH peroxidase activity. GSTA3-3 catalyzes the isomerization of intermediates in steroid hormone biosynthesis. GSTA4-4 preferentially catalyzes the GSH conjugation of alkenals.
Feature 1:GSH binding site (G-site) [chemical binding site]
Evidence:
Structure:1F3A; Mus musculus GSTA1-1 with bound GSH; contacts at 3.5A
Structure:1B48; Mus musculus GSTA4-4 with bound GSH; contacts at 3.5A
Structure:1TDI; Human GSTA3-3 with bound GSH; contacts at 3.5A
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.
Jiyao W et al.(2023). "The conserved domain database in 2023.",