UNILATERAL AMINOACYLATION SPECIFICITY BETWEEN BOVINE MITOCHONDRIA AND EUBACTERIA
UNILATERAL AMINOACYLATION SPECIFICITY BETWEEN BOVINE MITOCHONDRIA AND EUBACTERIA
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DOI：
10.1093/oxfordjournals.jbchem.a123397
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发表时间：
1991-03-01
影响因子：
2.7
通讯作者：
WATANABE, K
中科院分区：
文献类型：
--
作者：
KUMAZAWA, Y;HIMENO, H;WATANABE, K
本研究显示了牛线粒体和真细菌（大肠杆菌和嗜热热菌）在5种氨基酸特异性氨基酰化系统中的单侧特异性。线粒体合成酶能够对真细菌tRNA和线粒体tRNA进行充电，而真细菌合成酶不能有效地对线粒体tRNA进行充电。线粒体苯丙酰-、苏氨酸-、精氨酸-和赖氨酸-tRNA合成酶被证明对同源和非同源的大肠杆菌tRNA物种具有严格的电荷和区分作用，相应的大肠杆菌合成酶也具有同样的作用。相比之下，线粒体seryl-tRNA合成酶不仅使同源大肠杆菌丝氨酸tRNA物种发生错酰化，而且使非同源大肠杆菌tRNA物种发生广泛错酰化。这些结果表明线粒体和大肠杆菌氨基酰基-tRNA合成酶在tRNA识别机制上存在一定的保守性，即反密码子序列最容易被前四种合成酶识别，而seryl-tRNA合成酶的识别能力较弱。氨基酰化的单一性可能意味着线粒体合成酶的tRNA识别机制在某种程度上已经进化得比它们的真细菌对应物更简单，以响应动物线粒体tRNA的种类数量和结构元素的简化。
The present study shows unilateral aminoacylation specificity between bovine mitochondria and eubacteria (Escherichia coli and Thermus thermophilus) in five amino acid-specific aminoacylation systems. Mitochondrial synthetases were capable of charging eubacterial tRNA as well as mitochondrial tRNA, whereas eubacterial synthetases did not efficiently charge mitochondrial tRNA. Mitochondrial phenylalanyl-, threonyl-, arginyl-, and lysyl-tRNA synthetases were shown to charge and discriminate cognate E. coli tRNA species from noncognate ones strictly, as did the corresponding E. coli synthetases. By contrast, mitochondrial seryl-tRNA synthetase not only charged cognate E. coli serine tRNA species but also extensively misacylated noncognate E. coli tRNA species. These results suggest a certain conservation of tRNA recognition mechanisms between the mitochondrial and E. coli aminonoacyl-tRNA synthetases in that anticodon sequences are most likely to be recognized by the former four synthetases, but not sufficiently by the seryl-tRNA synthetase. The unilaterality in aminoacylation may imply that tRNA recognition mechanisms of the mitochondrial synthetases have evolved to be, to some extent, simpler than their eubacterial counterparts in response to simplifications in the species-number and the structural elements of animal mitochondrial tRNAs.