Leucine-specific domain modulates the aminoacylation and proofreading functional cycle of bacterial leucyl-tRNA synthetase
Leucine-specific domain modulates the aminoacylation and proofreading functional cycle of bacterial leucyl-tRNA synthetase
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DOI：
10.1093/nar/gkt185
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发表时间：
2013-03
影响因子：
14.9
通讯作者：
Wei-Qun Yan;M. Tan;G. Eriani;E. Wang
中科院分区：
文献类型：
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作者：
Wei-Qun Yan;M. Tan;G. Eriani;E. Wang
亮氨酸特异性结构域（LSD）是一个紧凑有序的模块，参与大多数亮氨酰-tRNA合成酶（LeuRS）中保守的KMSKS催化环的定位。然而，来自移动的支原体的LeuRS（MmLeuRS）具有四肽GKDG而不是LSD。在这里，我们表明，四肽GKDG可以赋予tRNA充电和转移后编辑活动时，移植到一个不活跃的大肠杆菌LeuRS（EcLeuRS），已删除其LSD。反过来，LSD与EcLeuRS的CP 1编辑结构域一起，在插入最小MmLeuRS的支架时可以合作，并且这产生了几乎与EcLeuRS一样活性的酶。此外，我们表明，LSD参与tRNALeu的识别，有利于结合的tRNA窝藏一个大的环中的可变arm. Additional分析建立，LSD中的Lys 598是关键的残留物的tRNA结合。Lys 598转化为Ala同时降低了tRNA结合强度和氨酰化和编辑能力，表明这些因素在LSD水平上微妙地连接和控制。本工作提供了一个新的框架之间的协同进化LeuRS和它的同源tRNA通过LSD。
The leucine-specific domain (LSD) is a compact well-ordered module that participates in positioning of the conserved KMSKS catalytic loop in most leucyl-tRNA synthetases (LeuRSs). However, the LeuRS from Mycoplasma mobile (MmLeuRS) has a tetrapeptide GKDG instead of the LSD. Here, we show that the tetrapeptide GKDG can confer tRNA charging and post-transfer editing activity when transplanted into an inactive Escherichia coli LeuRS (EcLeuRS) that has had its LSD deleted. Reciprocally, the LSD, together with the CP1-editing domain of EcLeuRS, can cooperate when inserted into the scaffold of the minimal MmLeuRS, and this generates an enzyme nearly as active as EcLeuRS. Further, we show that LSD participates in tRNALeu recognition and favours the binding of tRNAs harbouring a large loop in the variable arm. Additional analysis established that the Lys598 in the LSD is the critical residue for tRNA binding. Conversion of Lys598 to Ala simultaneously reduces the tRNA-binding strength and aminoacylation and editing capacities, indicating that these factors are subtly connected and controlled at the level of the LSD. The present work provides a novel framework of co-evolution between LeuRS and its cognate tRNA through LSD.