title: An evolutionary perspective on glutathione transferases inferred from class-theta glutathione transferase cDNA sequences.
abstract: We report the cDNA sequence for rat glutathione transferase (GST) subunit 5, which is one of at least three class Theta subunits in this species. This sequence, when compared with that of subunit 12 recently published by Ogura, Nishiyama, Okada, Kajita, Narihata, Watabe, Hiratsuka & Watabe [(1991) Biochem. Biophys. Res. Commun. 181, 1294-1300] proves that Theta is a separate multigene class of GST with little amino acid sequence identity with Mu-, Alpha- or Pi-class enzymes. The amino acid sequence identity of class-Theta subunits is highly conserved in rat, the fruitfly Drosophila, maize (Zea mays) and Methylobacterium, which suggests that this family is representative of the ancient progenitor GST gene and originates from the endosymbioses of a purple bacterium leading to the mitochondrion. The high conservation of class Theta brings into prominence that Alpha-, Mu- and Pi-class enzymes, which are not present in plants, derive from a Theta-class gene duplication before the divergence of fungi and animals and, given the binding properties of the Alpha-, Mu- and Pi-classes, suggests a role for these in the evolution of fungi and animals.
authors.affiliation: Department of Biochemistry and Molecular Biology, University College London, U.K.
authors.forename: S E
authors.initials: SE
authors.lastname: Pemble
authors.forename: J B
authors.initials: JB
authors.lastname: Taylor
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004247:DNA; D005982:Glutathione Transferase / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D051381:Rats; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014407:Tumor Cells, Cultured
chemical_list: D004247:DNA; D005982:Glutathione Transferase