Human mitochondrial TyrRS disobeys the tyrosine identity rules
Human mitochondrial TyrRS disobeys the tyrosine identity rules
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DOI：
10.1261/rna.7246805
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发表时间：
2005-05-01
期刊：
影响因子：
4.5
通讯作者：
Rudinger-Thirion, J
中科院分区：
文献类型：
--
作者：
Bonnefond, L;Frugier, M;Rudinger-Thirion, J
人类线粒体酪氨酰-tRNA合成酶(mt-TyrRS)具有真细菌和古生菌TyrRS的双重序列特征，特别是在含有识别N1-N72酪氨酸同源对的氨基酸的区域。这意味着人类mt-TyrRS已经失去了区分真细菌和线粒体tRNA(Tyr)典型的G1-C72对和古生菌和真核生物tRNA(Tyr)中存在的反向对C1-G72的能力。对野生型或突变的tRNatyr分子的功能分析证实了这一预期，表明mt-TyrRS氨基酰化具有类似的催化效率，其同源tRNA(Tyr)与G1-C72同源，其突变版本与C1-G72。这提供了TyrRS对N1-N72缺乏特异性的第一个例子，从而提供了TyrRS违反身份规则的第一个例子。系统发育的mt-TyrRS序列比较表明，人类mt-TyrRS的功能行为在所有脊椎动物mt-TyrRS中是保守的。
Human tyrosyl-tRNA synthetase from mitochondria (mt-TyrRS) presents dual sequence features characteristic of eubacterial and archaeal TyrRSs, especially in the region containing amino acids recognizing the N1-N72 tyrosine identity pair. This would imply that human mt-TyrRS has lost the capacity to discriminate between the G1-C72 pair typical of eubacterial and mitochondrial tRNA(Tyr) and the reverse pair C1-G72 present in archaeal and eukaryal tRNA(Tyr). This expectation was verified by a functional analysis of wild-type or mutated tRNATyr molecules, showing that mt-TyrRS aminoacylates with similar catalytic efficiency its cognate tRNA(Tyr) with G1-C72 and its mutated version with C1-G72. This provides the first example of a TyrRS lacking specificity toward N1-N72 and thus of a TyrRS disobeying the identity rules. Sequence comparisons of mt-TyrRSs across phylogeny suggest that the functional behavior of the human mt-TyrRS is conserved among all vertebrate mt-TyrRSs.