An Archaeal Dim2-Like Protein, aDim2p, Forms a Ternary Complex with a/eIF2α and the 3′ End Fragment of 16S rRNA
An Archaeal Dim2-Like Protein, aDim2p, Forms a Ternary Complex with a/eIF2α and the 3′ End Fragment of 16S rRNA
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DOI：
10.1016/j.jmb.2010.03.055
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发表时间：
2010-05-21
影响因子：
5.6
通讯作者：
Tanokura, Masaru
中科院分区：
文献类型：
--
作者：
Jia, Min Ze;Horita, Shoichiro;Tanokura, Masaru
Dim2p是18S rRNA成熟所需的真核小核糖体亚基RNA加工因子。在这里，我们证明了Dim2p的古生物同源物aDim2p与eIF2α的古生物同源物a/eIF2α和在溶液和晶体中都具有16S rRNA 3‘端序列的RNA片段形成了三元复合体。三元配合物的2.8埃晶体结构表明，aDim2p的两个KH结构域KH-1和-2分别与靶rRNA片段的反Shine-Dalgarno核心序列(CCUCC-3‘)和高度保守的相邻序列(5’-GGAUCA)结合。表面等离子体共振结果表明，aDim2p与靶rRNA片段的相互作用很强，解离常数为9.8×10(-10)M，并且aDim2p对16S rRNA的3‘端序列具有很强的核苷酸序列偏好。另一方面，aDim2p与分离的a亚基和完整的a/eIF2的α-β-γ复合体相互作用，与RNA结合无关。这些结果表明，aDim2p可能是一个识别16S rRNA 3‘端序列(5’-GAUCACCUCC-3‘)的古生菌前rRNA加工因子，并可能通过与其他蛋白质如a/eIF2和aRio2p相互作用而在体内发挥多种生物学作用。(C)2010爱思唯尔有限公司。保留所有权利。
Dim2p is a eukaryal small ribosomal subunit RNA processing factor required for the maturation of 18S rRNA. Here we show that an archaeal homolog of Dim2p, aDim2p, forms a ternary complex with the archaeal homolog of eIF2 alpha, a/eIF2 alpha, and the RNA fragment that possesses the 3' end sequence of 16S rRNA both in solution and in crystal. The 2.8-angstrom crystal structure of the ternary complex reveals that two KH domains of aDim2p, KH-1 and -2, are involved in binding the anti-Shine-Dalgarno core sequence (CCUCC-3') and a highly conserved adjacent sequence (5'-GGAUCA), respectively, of the target rRNA fragment. The surface plasmon resonance results show that the interaction of aDim2p with the target rRNA fragment is very strong, with a dissociation constant of 9.8 x 10(-10) M, and that aDim2p has a strong nucleotide sequence preference for the 3' end sequence of 16S rRNA. On the other hand, aDim2p interacts with the isolated a subunit and the intact alpha beta gamma complex of a/eIF2, irrespective of the RNA binding. These results suggest that aDim2p is a possible archaeal pre-rRNA processing factor recognizing the 3' end sequence (5'-GAUCACCUCC-3') of 16S rRNA and may have multiple biological roles in vivo by interacting with other proteins such as a/eIF2 and aRio2p. (C) 2010 Elsevier Ltd. All rights reserved.