L-Arginine recognition by yeast arginyl-tRNA synthetase
L-Arginine recognition by yeast arginyl-tRNA synthetase
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DOI：
10.1093/emboj/17.18.5438
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发表时间：
1998-09-15
期刊：
影响因子：
11.4
通讯作者：
Moras, D
中科院分区：
文献类型：
--
作者：
Cavarelli, J;Delagoutte, B;Moras, D
来自酿酒酵母的精氨酰-tRNA 合成酶 (ArgRS) 的晶体结构，一种 I 类氨酰基-tRNA 合成酶 (aaRS)，其 L-精氨酸与活性位点结合，已在 2.75 埃分辨率下解析，并精炼至 19.7% 的晶体学 R 因子。 ArgRS 主要由 α 螺旋组成，可分为五个结构域，包括 I 类特异性活性位点。 N 末端结构域与一些完全不相关的蛋白质表现出惊人的相似性，并定义了一个应该参与特定 tRNA 识别的模块。 C 末端结构域是假定的反密码子结合模块，显示出与大肠杆菌甲硫氨酰-tRNA 合成酶高度相似的全α螺旋折叠，虽然 ArgRS 需要 tRNA(Arg) 来完成氨酰化反应的第一步，但结果表明它的存在并不是 L-精氨酸结合的先决条件。 L-精氨酸的所有氢键形成能力都被蛋白质用于特异性识别。胍基团与两个酸性残基形成两个盐桥相互作用，并与一个酪氨酸残基形成一个氢键；这三个残基在所有ArgRS序列中都是严格保守的。该酪氨酸在其他 I 类 aaRS 活性位点中也保守，但发挥多种功能作用。 ArgRS 结构允许定义 I 类 aaRS 中序列比对和子类定义的新框架。
The crystal structure of arginyl-tRNA synthetase (ArgRS) from Saccharomyces cerevisiae, a class I aminoacyl-tRNA synthetase (aaRS), with L-arginine bound to the active site has been solved at 2.75 Angstrom resolution and refined to a crystallographic R-factor of 19.7%. ArgRS is composed predominantly of alpha-helices and can be divided into five domains, including the class I-specific active site. The N-terminal domain shows striking similarity to some completely unrelated proteins and defines a module which should participate in specific tRNA recognition. The C-terminal domain, which is the putative anticodon-binding module, displays an all-alpha-helix fold highly similar to that of Escherichia coli methionyl-tRNA synthetase, While ArgRS requires tRNA(Arg) for th, first step of the aminoacylation reaction, the results show that its presence is not a prerequisite for L-arginine binding. All H-bond-forming capability of L-arginine is used by the protein for the specific recognition. The guanidinium group forms two salt bridge interactions with two acidic residues, and one H-bond with a tyrosine residue; these three residues are strictly conserved in all ArgRS sequences. This tyrosine is also conserved in other class I aaRS active sites but plays several functional roles. The ArgRS structure allows the definition of a new framework for sequence alignments and subclass definition in class I aaRSs.