The carboxy-terminal domain of the DExD/H protein YxiN is sufficient to confer specificity for 23 S rRNA
The carboxy-terminal domain of the DExD/H protein YxiN is sufficient to confer specificity for 23 S rRNA
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DOI：
10.1016/s0022-2836(02)01140-3
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发表时间：
2002-12-06
影响因子：
5.6
通讯作者：
Uhlenbeck, OC
中科院分区：
文献类型：
--
作者：
Kossen, K;Karginov, FV;Uhlenbeck, OC
DEx D/H蛋白被认为通过破坏RNA螺旋和RNA-蛋白相互作用来调节RNA和核糖核蛋白复合物的结构。所有DEx D/H蛋白都含有一个双结构域催化核心，使其具有RNA依赖性atp酶和RNA解旋酶活性。催化核心的两侧可能有辅助结构域，这些辅助结构域被提出赋予底物特异性并促进单个蛋白质的独特功能。大肠杆菌DEX D/H蛋白DbpA及其枯草芽孢杆菌同源物YxiN具有相似的75aa羧基末端结构域，均特异性靶向23s rRNA。在这里，我们通过表征一个嵌合体，证明YxiN的羧基末端结构域足以赋予RNA特异性，该结构域附加在大肠杆菌smp（一种DEX D/H蛋白，没有明显的底物特异性）的核心结构域上。嵌合体的RNA依赖性atp酶和RNA解旋酶活性均被23s rRNA特异性激活，并被发夹92 （YxiN的关键识别元件）的序列变化所消除。这些数据支持一个模型，其中羧基末端结构域结合发夹92以靶向蛋白23s rRNA。(C) 2002 Elsevier Science Ltd.版权所有。
DEx D/H proteins are believed to modulate the structures of RNAs and ribonucleoprotein complexes by disrupting RNA helices and RNA-protein interactions. All DEx D/H proteins contain a two-domain catalytic core that enables their RNA-dependent ATPase and RNA helicase activities. The catalytic core may be flanked by ancillary domains that are proposed to confer substrate specificity and facilitate the unique functions of individual proteins. The Escherichia coli DEX D/H protein DbpA and its Bacillus subtilis ortholog YxiN have similar 75aa carboxy-terminal domains, and both proteins are specifically targeted to 23 S rRNA. Here we demonstrate that the carboxy-terminal domain of YxiN is sufficient to confer RNA specificity by characterizing a chimera in which this domain is appended to the core domains of E. coli SrmB, a DEX D/H protein with no apparent substrate specificity. Both the RNA-dependent ATPase and RNA helicase activities of the chimera are specifically activated by 23 S rRNA and abolished by sequence changes within hairpin 92, a critical recognition element for YxiN. These data support a model in which the carboxyterminal domain binds hairpin 92 to target the protein to 23 S rRNA. (C) 2002 Elsevier Science Ltd. All rights reserved.