RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama, Japan.
Nat Struct Mol Biol. 2010 Sep;17(9):1136-43. doi: 10.1038/nsmb.1889. Epub 2010 Aug 22.
Aminoacyl-tRNA synthetase (aaRS) paralogs with unknown functions exist in various species. We now report novel 'protein lysylation' by an Escherichia coli lysyl-tRNA synthetase paralog, GenX/PoxA/YjeA. X-ray crystallographic analysis shows that the structure of the GenX protein resembles that of a class II aaRS. Further in vitro studies reveal that it specifically aminoacylates EF-P with lysine. The shape of the protein substrate mimics that of the L-shaped tRNA, and its lysylation site corresponds to the tRNA 3' end. Thus, we show how the aaRS architecture can be adapted to achieve aminoacylation of a specific protein. Moreover, in vivo analyses reveal that the translation elongation factor P (EF-P) lysylation by GenX is enhanced by YjeK (lysine 2,3-aminomutase paralog), which is encoded next to the EF-P gene, and might convert alpha-lysyl-EF-P to beta-lysyl-EF-P. In vivo analyses indicate that the EF-P modification by GenX and YjeK is essential for cell survival.
在各种物种中存在具有未知功能的氨酰-tRNA 合成酶（aaRS）同工酶。我们现在报告大肠杆菌赖氨酸-tRNA 合成酶同工酶的新型“蛋白质赖氨酸化”，即 GenX/PoxA/YjeA。X 射线晶体学分析表明，GenX 蛋白的结构类似于 II 类 aaRS。进一步的体外研究表明，它特异性地将赖氨酸氨酰化到 EF-P 上。蛋白质底物的形状类似于 L 形 tRNA，其赖氨酸化位点对应于 tRNA 的 3'端。因此，我们展示了 aaRS 结构如何适应实现特定蛋白质的氨酰化。此外，体内分析表明，GenX 对延伸因子 P（EF-P）的赖氨酸化作用由紧邻 EF-P 基因编码的 YjeK（赖氨酸 2,3-氨基变位酶同工酶）增强，并且可能将 alpha-lysyl-EF-P 转化为 beta-lysyl-EF-P。体内分析表明，GenX 和 YjeK 对 EF-P 的修饰对于细胞存活至关重要。
