Pemble S E, Taylor J B
Department of Biochemistry and Molecular Biology, University College London, U.K.
Biochem J. 1992 Nov 1;287 ( Pt 3)(Pt 3):957-63. doi: 10.1042/bj2870957.
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.
我们报道了大鼠谷胱甘肽转移酶（GST）亚基5的cDNA序列，它是该物种中至少三种θ类亚基之一。将此序列与小仓、西山、冈田、梶田、成幡、渡边、平冢和渡边最近发表的亚基12的序列[（1991年）《生物化学与生物物理学研究通讯》181, 1294 - 1300]相比较，证明θ是GST的一个独立的多基因类，与μ类、α类或π类酶的氨基酸序列同源性很低。θ类亚基的氨基酸序列同源性在大鼠、果蝇、玉米（玉米）和甲基杆菌中高度保守，这表明该家族代表了古老的祖先GST基因，起源于导致线粒体的紫色细菌的内共生。θ类的高度保守突出了植物中不存在的α类、μ类和π类酶，是在真菌和动物分化之前从θ类基因复制而来的，并且鉴于α类、μ类和π类的结合特性，表明它们在真菌和动物的进化中发挥了作用。
