Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA.
FEBS Lett. 2010 Jul 16;584(14):3055-60. doi: 10.1016/j.febslet.2010.05.036. Epub 2010 May 24.
Aminoacyl-tRNA synthetases produce aminoacyl-tRNAs, essential substrates for accurate protein synthesis. Beyond their central role in translation some of these enzymes or their orthologs are recruited for alternative functions, not always related to their primary cellular role. We investigate here the enzymatic properties of GenX (also called PoxA and YjeA), an ortholog of bacterial class II lysyl-tRNA synthetase. GenX is present in most Gram-negative bacteria and is homologous to the catalytic core of lysyl-tRNA synthetase, but it lacks the amino terminal anticodon binding domain of the latter enzyme. We show that, in agreement with its well-conserved lysine binding site, GenX can activate in vitro l-lysine and lysine analogs, but does not acylate tRNA(Lys) or other cellular RNAs.
氨酰-tRNA 合成酶生成氨酰-tRNA，这是准确蛋白质合成的必需底物。除了在翻译中的核心作用外，这些酶或其同源物中的一些被招募用于替代功能，这些功能并不总是与其主要细胞功能相关。我们在这里研究 GenX（也称为 PoxA 和 YjeA）的酶学性质，GenX 是细菌 II 类赖氨酸-tRNA 合成酶的同源物。GenX 存在于大多数革兰氏阴性菌中，与赖氨酸-tRNA 合成酶的催化核心同源，但它缺少后者酶的氨基末端反密码子结合结构域。我们表明，与保守的赖氨酸结合位点一致，GenX 可以体外激活 l-赖氨酸和赖氨酸类似物，但不能酰化 tRNA（Lys）或其他细胞 RNA。
