Contribution of RNA conformation to the stability of a high-affinity RNA-protein complex
Contribution of RNA conformation to the stability of a high-affinity RNA-protein complex
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DOI：
10.1021/ja000837u
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发表时间：
2000-07-26
影响因子：
15
通讯作者：
Baranger, AM
中科院分区：
文献类型：
--
作者：
Luchansky, SJ;Nolan, SJ;Baranger, AM
RNA折叠成复杂的二级和三级结构，呈现出具有不同方向功能基团的RNA结合蛋白。1与RNA序列特异性结合的蛋白质通常与RNA的单链区域结合，因为它们比A型RNA螺旋暴露出更易接近和序列依赖性的功能基团阵列。单链区域通常在构象上受到相邻螺旋的限制。这种预组织可能有助于许多（如果不是大多数）RNA-蛋白质复合物的稳定性，但这种贡献的定量分析是罕见的。我们发现，RNA二级结构的贡献至少3.5千卡/摩尔的U1 A-RNA复合物的稳定性，在很大程度上通过预组织的单链靶序列的核苷酸与U1A.U1A的最佳相互作用是一个组成部分的U1小核核糖核蛋白颗粒（snRNP）的剪接体的一部分，剪接大多数真核前mRNA。2 U1 A的N端RNP结构域负责RNA识别，并与U1 snRNA中的茎环2结合（图1A）。3 RNP结构域是最常见和最具特征的RNA结合结构域之一。具有该结构域的蛋白质能够在多种结构背景下结合单链RNA。4
RNA folds into complicated secondary and tertiary structures that present RNA-binding proteins with functional groups in diverse orientations. 1 Proteins that bind to RNA sequencespecifically usually bind to single-stranded regions of RNA because they expose a more accessible and sequence-dependent array of functional groups than do A-form RNA helices. Singlestranded regions are often conformationally restrained by adjacent helices. This preorganization may contribute to the stability of many, if not most, RNA-protein complexes, but quantitative analyses of this contribution are rare. We show that RNA secondary structure contributes at least 3.5 kcal/mol to the stability of the U1A-RNA complex, in large part by preorganizing nucleotides of the single-stranded target sequence for optimal interactions with U1A.U1A is a component of the U1 small nuclear ribonucleoprotein particle (snRNP) that forms part of the spliceosome, which splices most eukaryotic pre-mRNA. 2 An N-terminal RNP domain of U1A is responsible for RNA recognition and binds to stem loop 2 in U1 snRNA (Figure 1A). 3 The RNP domain is one of the most common and best-characterized RNA binding domains. Proteins with this domain are able to bind single-stranded RNA in a variety of structural contexts. 4