EVOLUTION OF ESSENTIAL TRANSLATIONAL PATHWAYS IN ARCHAEA

(改编自调查员摘要)：这项提案将调查一 古文字翻译设备的独特组件的数量，其 对于信实地将信使核糖核酸解码成蛋白质来说是必不可少的。正确的氨基- 准确的核糖体翻译需要乙酰化的tRNA。他们是 通常认为仅由氨基酰-tRNA提供 合成酶，一种普遍存在的高度保守的酶家族 整个活生生的王国。然而，许多生物体和一些细胞器 至少缺少一种氨基酰基-tRNA合成酶--谷氨酰基-tRNA合成酶。 在这些生物体和细胞器中，Gln-tRNA是由氨化形成的 谷氨酸被错误地酰化成t-RNA Gln。私家侦探最近显示， 在古生代也存在类似的合成ASN-tRNA的途径。 因此，氨基酸的转化，以前只与 中间代谢，是翻译保真度的关键要求 尤其是在古生代。古生代氨基酰tRNA的第二个独特特征 形成是使用与任何一种尚未发现的酶不同的酶 真细菌或真核细胞产生赖氨酰-tRNA和半胱氨酰-tRNA。

(adapted from investigator's abstract): This proposal will investigate a number of unique components of the archael translation apparatus which are essential for the faithful decoding of mRNA into protein. Correctly amino- aceylated tRNAs are required for accurate ribosomal translation. They are generally believed to be provided solely by the aminoacyl-tRNA synthetases, a ubiquitous and highly conserved family of enzymes found throughout the living kingdom. However, many organisms and some organelles lack at least one aminoacyl-tRNA synthetase, glutaminyl-tRNA synthetase. In these organisms and organelles Gln-tRNA is formed by the amidation of glutamate mis acylated to t-RNA Gln. The P.I. has recently shown that a comparable pathway also exists for the synthesis of Asn-tRNA in Archaea. Thus amino acid transformations, previously only associated with intermediary metabolism, are a key requirement for translational fidelity particularly in Archaea. A second unique feature of archael aminoacyl-tRNA formation is the use of enzymes distinct from any yet found in either eubacteria or eukaryotes to generate lysyl-tRNA and cysteinyl-tRNA.