A minimalist glutamyl-tRNA synthetase dedicated to aminoacylation of the tRNAAsp QUC anticodon
A minimalist glutamyl-tRNA synthetase dedicated to aminoacylation of the tRNAAsp QUC anticodon
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DOI：
10.1093/nar/gkh608
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发表时间：
2004-05-01
影响因子：
14.9
通讯作者：
Kern, D
中科院分区：
文献类型：
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作者：
Blaise, M;Becker, HD;Kern, D
大肠杆菌编码的YadB蛋白与谷氨酰胺- trna合成酶的催化核心具有34%的同源性，但缺乏抗密码子结合结构域。我们发现YadB是一种tRNA修饰酶，它明显地将tRNA(Asp) QUC反密码子摆动位置上的修饰核苷基（queuosine残基）谷氨酰化。这一结论得到了多种生化数据的支持，也得到了从大肠杆菌tRNA-鸟苷转糖基化酶缺失菌株中分离的tRNA-鸟苷转糖基化酶无法将tRNA（Asp）谷氨酰胺化的结果的支持。原核生物中编码YadB蛋白的tRNA（Asp）反密码子茎和tRNA（Glu）氨基酸受体茎的结构相似性表明，这些tRNA修饰酶（我们将其重新命名为glutamyl-Q tRNA（Asp）合成酶）的功能在原核生物中是保守的。
Escherichia coli encodes YadB, a protein displaying 34% identity with the catalytic core of glutamyl-tRNA synthetase but lacking the anticodon-binding domain. We show that YadB is a tRNA modifying enzyme that evidently glutamylates the queuosine residue, a modified nucleoside at the wobble position of the tRNA(Asp) QUC anticodon. This conclusion is supported by a variety of biochemical data and by the inability of the enzyme to glutamylate tRNA(Asp) isolated from an E.coli tRNA-guanosine transglycosylase minus strain deprived of the capacity to exchange guanosine 34 with queuosine. Structural mimicry between the tRNA(Asp) anticodon stem and the tRNA(Glu) amino acid acceptor stem in prokaryotes encoding YadB proteins indicates that the function of these tRNA modifying enzymes, which we rename glutamyl-Q tRNA(Asp) synthetases, is conserved among prokaryotes.