GST conjugates reduced glutathione to a variety of targets including S-crystallin from squid, the eukaryotic elongation factor 1-gamma, the HSP26 family of stress-related proteins and auxin-regulated proteins in plants. Stringent starvation proteins in E. coli are also included in the alignment but are not known to have GST activity. The glutathione molecule binds in a cleft between N and C-terminal domains. The catalytically important residues are proposed to reside in the N-terminal domain [1]. In plants, GSTs are encoded by a large gene family (48 GST genes in Arabidopsis) and can be divided into the phi, tau, theta, zeta, and lambda classes [2].

1: Three-dimensional structure of Escherichia coli glutathione S-transferase complexed with glutathione sulfonate: catalytic roles of Cys10 and His106. Nishida M, Harada S, Noguchi S, Satow Y, Inoue H, Takahashi K; J Mol Biol 1998;281:135-147. PMID:9680481

2: Plant glutathione transferases. Dixon DP, Lapthorn A, Edwards R; Genome Biol 2002;3:REVIEWS3004. PMID:11897031