Characterization of the molecular basis of group II intron RNA recognition by CRS1-CRM domains
Characterization of the molecular basis of group II intron RNA recognition by CRS1-CRM domains
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DOI：
10.1074/jbc.m710488200
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发表时间：
2008-08-22
影响因子：
4.8
通讯作者：
Ostersetzer-Biran, Oren
中科院分区：
文献类型：
--
作者：
Keren, Ido;Klipcan, Liron;Ostersetzer-Biran, Oren
CRM(叶绿体RNA剪接和核糖体成熟)是最近发现的一个古老的RNA结合域，仅保留在真核基因组中的植物谱系中。在细菌中，CRM结构域以参与核糖体成熟的单一结构域蛋白质的形式存在，而在植物中，它们存在于一个包含一到四个重复序列的蛋白质家族中。这个具有多个CRM结构域的家族中的几个成员被证明是剪接特定的可塑性II组内含子所必需的。对玉米中的其中一个因子CRS1进行了详细的生化分析，结果表明它与单个II组内含子具有很高的亲和力和特异性结合，它促进了内含子的剪接，即由叶绿体编码的atpF内含子RNA。通过与两个内含子区域的结合，CRS1引导atpF内含子RNA折叠成其预测的“催化活性”形式。为了了解多个CRM结构域是如何协同作用实现与RNA的高亲和力序列特异性结合的，我们分析了CRS1中每个单独的CRM结构域的RNA结合亲和力和特异性；而CRM3与RNA紧密结合，而CRM1则与atpF内含子结构域I中的一个独特区域特异结合。CRM2仅显示出低结合亲和力，似乎也与定位于I、III和IV结构域的区域形成特异性相互作用。我们进一步表明，CRM结构域与众所周知的RNA识别基序结构域有相似的结构和RNA结合特征。
CRM (chloroplast RNA splicing and ribosome maturation) is a recently recognized RNA-binding domain of ancient origin that has been retained in eukaryotic genomes only within the plant lineage. Whereas in bacteria CRM domains exist as single domain proteins involved in ribosome maturation, in plants they are found in a family of proteins that contain between one and four repeats. Several members of this family with multiple CRM domains have been shown to be required for the splicing of specific plastidic group II introns. Detailed biochemical analysis of one of these factors in maize, CRS1, demonstrated its high affinity and specific binding to the single group II intron whose splicing it facilitates, the plastid-encoded atpF intron RNA. Through its association with two intronic regions, CRS1 guides the folding of atpF intron RNA into its predicted "catalytically active" form. To understand how multiple CRM domains cooperate to achieve high affinity sequence-specific binding to RNA, we analyzed the RNA binding affinity and specificity associated with each individual CRM domain in CRS1; whereas CRM3 bound tightly to the RNA, CRM1 associated specifically with a unique region found within atpF intron domain I. CRM2, which demonstrated only low binding affinity, also seems to form specific interactions with regions localized to domains I, III, and IV. We further show that CRM domains share structural similarities and RNA binding characteristics with the well known RNA recognition motif domain.