A naturally occurring nonapeptide functionally compensates for the CP1 domain of leucyl-tRNA synthetase to modulate aminoacylation activity
A naturally occurring nonapeptide functionally compensates for the CP1 domain of leucyl-tRNA synthetase to modulate aminoacylation activity
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天然存在的九肽在功能上补偿亮氨酰-tRNA 合成酶的 CP1 结构域以调节氨酰化活性
DOI：
10.1042/bj20111925
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发表时间：
2012-04-15
影响因子：
4.1
通讯作者：
Wang, En-Duo
中科院分区：
文献类型：
--
作者：
Tan, Min;Yan, Wei;Wang, En-Duo
aaRS（氨酰-tRNA合成酶）通过催化氨酰-tRNA的形成来建立遗传密码的规则。氨基酰化的质量控制通过编辑活性来实现，其通常由离散的编辑结构域进行。对于LeuRS（亮氨酰-tRNA合成酶），CP 1（连接肽1）结构域是负责水解带错电荷的tRNA的编辑结构域。CP 1结构域普遍存在于LeuRS中，但MmLeuRS（支原体移动的LeuRS）除外。MmLeuRS中CP 1的替代物是九肽（MmLinker）。在本研究中，我们表明，MmLinker，这是关键的氨酰化活性的MmLeuRS，可以赋予显着的tRNA充电活性的非活性的CP 1-删除的LeuRS从大肠杆菌（EcLeuRS）和Aquifex aeolicus（AaLeuRS）。此外，来自EcLeuRS的CP 1可以在功能上补偿MmLinker并赋予MmLeuRS转移后编辑能力。这些调查提供了一个机制框架的模块化建设的aaRS和他们的协调，以实现催化效率和保真度。这些结果也表明LeuRS的转移前编辑功能来源于其保守的合成结构域，并为进一步研究其机制提供了参考。
aaRSs (aminoacyl-tRNA synthetases) establish the rules of the genetic code by catalysing the formation of aminoacyl-tRNA. The quality control for arninoacylation is achieved by editing activity, which is usually carried out by a discrete editing domain. For LeuRS (leucyl-tRNA synthetase), the CP1 (connective peptide 1) domain is the editing domain responsible for hydrolysing mischarged tRNA. The CP1 domain is universally present in LeuRSs, except MmLeuRS (Mycoplasma mobile LeuRS). The substitute of CP1 in MmLeuRS is a nonapeptide (MmLinker). In the present study, we show that the MmLinker, which is critical for the aminoacylation activity of MmLeuRS, could confer remarkable tRNA-charging activity on the inactive CP1-deleted LeuRS from Escherichia coli (EcLeuRS) and Aquifex aeolicus (AaLeuRS). Furthermore, CP1 from EcLeuRS could functionally compensate for the MmLinker and endow MmLeuRS with post-transfer editing capability. These investigations provide a mechanistic framework for the modular construction of aaRSs and their co-ordination to achieve catalytic efficiency and fidelity. These results also show that the pre-transfer editing function of LeuRS originates from its conserved synthetic domain and shed light on future study of the mechanism.