Pemble S E, Wardle A F, Taylor J B
Cancer Research Campaign Molecular Toxicology Group, University College London, U.K.
Biochem J. 1996 Nov 1;319 ( Pt 3)(Pt 3):749-54. doi: 10.1042/bj3190749.
We have isolated a cDNA clone that encodes rat glutahione S-transferase (GST) subunit 13, a GST originally isolated from rat liver mitochondrial matrix by Harris, Meyer, Coles and Ketterer [(1991) Biochem. J. 278, 137-141]. The 896 bp cDNA contains an open reading frame of 678 bp encoding a deduced protein sequence of which the first 33 residues (excluding the initiation methionine residue) correspond to the N-terminal sequence reported by Harris et al. Hence like many other nuclear-encoded, mitochondrially located proteins, there is no cleavable mitochondrial presequence at the N-terminus. GST subunit 13 was originally placed into the Theta class of GSTs on the basis of sequence identity at the N-terminus; however, this is the only identity with the Theta class and in fact GST subunit 13 shows little sequence similarity to any of the known GST classes. Most importantly it lacks the SNAIL/TRAIL motif that has so far been a characteristic of soluble GSTs, although it does possess a second motif (FGXXXXVXXVDGXXXXXF) reported for GST-related proteins (Koonin, Mushegian, Tatusov, Altschul, Bryant, Bork and Valencia [(1994) Protein Sci. 3, 2045-2054]. Southern and Northern blot analyses of rat DNA and mRNA are consistent with GST subunit 13's being the product of a single hybridizing gene locus. Searches of EST databases identified numerous similar human DNA sequences and a single pig sequence. We have derived a human cDNA sequence from these EST sequences which shows a high nucleotide similarity (77%) to rat GST subunit 13. The largest open reading frame is identical in length with subunit 13 and yields a deduced protein sequence identity of 70%. Most unusually the 3' non-coding nucleotide sequence identity is also 77%. We conclude that these cDNAs belong to a novel GST class hereby designated Kappa, with the rat GST subunit 13 gene designated rGSTK1 and the human gene being called hGSTK1.
我们分离出了一个编码大鼠谷胱甘肽S-转移酶（GST）亚基13的cDNA克隆，该GST最初由哈里斯、迈耶、科尔斯和凯特勒从大鼠肝脏线粒体基质中分离得到[（1991年）《生物化学杂志》278卷，第137 - 141页]。这个896 bp的cDNA包含一个678 bp的开放阅读框，编码一个推导的蛋白质序列，其中前33个残基（不包括起始甲硫氨酸残基）与哈里斯等人报道的N端序列相对应。因此，与许多其他核编码的线粒体定位蛋白一样，其N端没有可切割的线粒体前导序列。GST亚基13最初基于N端的序列同一性被归入GST的θ类；然而，这是与θ类唯一的同一性，实际上GST亚基13与任何已知的GST类的序列相似性都很小。最重要的是，它缺乏迄今为止可溶性GST所具有的SNAIL/TRAIL基序，尽管它确实拥有一个为GST相关蛋白报道的第二个基序（FGXXXXVXXVDGXXXXXF）[库宁、穆舍吉安、塔图索夫、阿尔茨舒尔、布莱恩特、博尔克和巴伦西亚（1994年）《蛋白质科学》3卷，第2045 - 2054页]。对大鼠DNA和mRNA的Southern和Northern印迹分析与GST亚基13是单个杂交基因座的产物一致。对EST数据库的搜索鉴定出许多相似的人类DNA序列和一个猪序列。我们从这些EST序列中推导得到了一个人类cDNA序列，它与大鼠GST亚基13具有高度的核苷酸相似性（77%）。最大的开放阅读框长度与亚基13相同，推导的蛋白质序列同一性为70%。最不寻常的是，3'非编码核苷酸序列同一性也是77%。我们得出结论，这些cDNA属于一个新的GST类，在此命名为κ类，大鼠GST亚基13基因命名为rGSTK1，人类基因称为hGSTK1。
