Two tyrosine residues outside the editing active site in Giardia lamblia leucyl-tRNA synthetase are essential for the post-transfer editing.
Two tyrosine residues outside the editing active site in Giardia lamblia leucyl-tRNA synthetase are essential for the post-transfer editing.
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DOI：
10.1016/j.bbrc.2009.06.070
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发表时间：
2009-08
影响因子：
3.1
通讯作者：
Xiao-Long Zhou;E. Wang
中科院分区：
文献类型：
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作者：
Xiao-Long Zhou;E. Wang
亮氨酰-tRNA合成酶（LeuRS）负责Leu-tRNA的合成。连接肽1（connecticpeptide 1，CP 1）结构域插入到Rossmann核苷酸结合折叠中，具有编辑活性位点，可将错电荷的tRNA Leu与非同源氨基酸水解，从而保证蛋白质合成的高保真性。不同构象的LeuRS与tRNALeu 3 ′端的共晶体结构表明，tRNALeu 3 ′端在合成和编辑活性位点之间动态穿梭，并与CP 1结构域发生直接特异的相互作用。在此，我们报道了贾第虫LeuRS（GlLeuRS）CP 1结构域编辑活性位点外的Y515和Y 520通过影响与带错电荷的tRNALeu的结合亲和力而对转移后编辑至关重要。Y515和Y 520上的突变也在不同程度上降低了tRNA亮氨酸充电活性，但对亮氨酸激活没有影响。这些结果为古/真核LeuRS中tRNALeu 3 ′端与CP 1结构域相互作用提供了一些生物化学知识。
Leucyl-tRNA synthetase (LeuRS) is responsible for the Leu-tRNALeusynthesis. The connective peptide 1 (CP1) domain inserted into the Rossmann nucleotide binding fold possesses editing active site to hydrolyze the mischarged tRNALeuwith noncognate amino acid, then to ensure high fidelity of protein synthesis. A few co-crystal structures of LeuRS with tRNALeuin different conformations revealed that tRNALeu3′ end shuttled between synthetic and editing active sites dynamically with direct and specific interaction with the CP1 domain. Here, we reported that Y515 and Y520 outside the editing active site of CP1 domain of Giardia lamblia LeuRS (GlLeuRS) are crucial for post-transfer editing by influencing the binding affinity with mischarged tRNALeu. Mutations on Y515 and Y520 also decreased tRNALeucharging activity to various extents but had no effect on leucine activation. Our results gave some biochemical knowledge about interaction of tRNALeu3′ end with the CP1 domain in archaeal/eukaryotic LeuRS.