tRNA integrity is a prerequisite for rapid CCA addition: Implication for quality control
tRNA integrity is a prerequisite for rapid CCA addition: Implication for quality control
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DOI：
10.1016/j.jmb.2008.04.005
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发表时间：
2008-06-06
影响因子：
5.6
通讯作者：
Hou, Ya-Ming
中科院分区：
文献类型：
--
作者：
Dupasquier, Marcel;Kim, Sangbumn;Hou, Ya-Ming
CCA添加到3'末端是tRNA成熟的重要步骤。CCA酶的高分辨率晶体结构揭示了与由受体茎和T茎环组成的tRNA微螺旋结构域的初级酶接触。RNA和DNA微螺旋是CCA在稳态动力学中的有效底物。然而，与结构模型和稳态实验相反，我们在这里通过单周转动力学表明，微螺旋是大肠杆菌CCA酶的不足底物，并且只有全长tRNA是动力学胜任的。即使是在T环中全长tRNA骨架上的切口，或者像在反密码子环中那样远离微螺旋结构域，也会阻止有效的CCA添加。这些结果表明CCA酶提供的动力学质量控制，以检查tRNA分子的完整性，并从进一步成熟中区分有切口或受损的物种。(c)2008爱思唯尔有限公司保留所有权利。
CCA addition to the 3' end is an essential step in tRNA maturation. High-resolution crystal structures of the CCA enzymes reveal primary enzyme contact with the tRNA minihelix domain, consisting of the acceptor stem and T stem-loop. RNA and DNA minihelices are efficient substrates for CCA addition in steady-state kinetics. However, in contrast to structural models and steady-state experiments, we show here by single-turnover kinetics that minihelices are insufficient substrates for the Escherichia coli CCA enzyme and that only the full-length tRNA is kinetically competent. Even a nick in the full-length tRNA backbone in the T loop, or as far away from the minihelix domain as in the anticodon loop, prevents efficient CCA addition. These results suggest a kinetic quality control provided by the CCA enzyme to inspect the integrity of the tRNA molecule and to discriminate against nicked or damaged species from further maturation. (c) 2008 Elsevier Ltd. All rights reserved.