Structure of tandem RNA recognition motifs from polypyrimidine tract binding protein reveals novel features of the RRM fold
Structure of tandem RNA recognition motifs from polypyrimidine tract binding protein reveals novel features of the RRM fold
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DOI：
10.1093/emboj/19.12.3132
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发表时间：
2000-06-15
期刊：
影响因子：
11.4
通讯作者：
Curry, S
中科院分区：
文献类型：
--
作者：
Conte, MR;Grüne, T;Curry, S
聚嘧啶束结合蛋白（PTB）是一种含有4个RNA识别基序（RRMs）的RNA结合蛋白，参与小核糖核酸病毒内部核糖体进入位点的mrna前剪接和翻译起始。先前的序列比较表明，PTB是一个非典型的RRM蛋白，含有RRM 3和4的PTB片段的溶液结构表明，该蛋白由两个由长而灵活的连接体连接的结构域组成。这两个畴在溶液中独立翻滚，没有固定的相对取向。除了RRM结构域特有的β - α - β - α - β - α - β拓扑结构外，PTB RRM-3的c端延伸还包含了意想不到的第五β链，它延伸了RNA结合表面。RRM-3中连接β 4和β 5的长而无序的多肽位于RNA结合表面上方，可能有助于RNA识别。突变分析表明，RRM-3和RRM-4都有助于RNA结合特异性。尽管其序列不同寻常，但PTB以类似于其他RRM蛋白的方式结合RNA。
Polypyrimidine tract binding protein (PTB), an RNA binding protein containing four RNA recognition motifs (RRMs), is involved in both pre-mRNA splicing and translation initiation directed by picornaviral internal ribosome entry sites. Sequence comparisons previously indicated that PTB is a non-canonical RRM protein, The solution structure of a PTB fragment containing RRMs 3 and 4 shows that the protein consists of two domains connected by a long, flexible linker. The two domains tumble independently in solution, having no fixed relative orientation. In addition to the beta alpha beta beta alpha beta topology, which is characteristic of RRM domains, the C-terminal extension of PTB RRM-3 incorporates an unanticipated fifth beta-strand, which extends the RNA binding surface, The long, disordered polypeptide connecting beta 4 and beta 5 in RRM-3 is poised above the RNA binding surface and is likely to contribute to RNA recognition, Mutational analyses show that both RRM-3 and RRM-4 contribute to RNA binding specificity and that, despite its unusual sequence, PTB binds RNA in a manner akin to that of other RRM proteins.