Structural basis of nucleic-acid recognition and double-strand unwinding by the essential neuronal protein Pur-alpha
Structural basis of nucleic-acid recognition and double-strand unwinding by the essential neuronal protein Pur-alpha
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DOI：
10.7554/elife.11297
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发表时间：
2016-01-08
期刊：
影响因子：
7.7
通讯作者：
Niessing, Dierk
中科院分区：
文献类型：
--
作者：
Weber, Janine;Bao, Han;Niessing, Dierk
神经元DNA/RNA结合蛋白PUR-α是一种转录调节因子，也是mRNA定位的核心因子。Pur-α基因缺陷小鼠出生后死于多效性神经元缺陷。在这里，我们报道了与单链DNA形成的复合体中PUR-α的DNA/RNA结合域的晶体结构。它揭示了碱基特异性识别，并为5q31.3微缺失综合征中点突变的影响提供了分子解释。生化和核磁共振数据与晶体结构一致，表明Pur-α以相同的方式与DNA和RNA结合，表明在两种神经退行性RNA病中，三核苷酸和六核苷酸重复RNA的结合模式。此外，基于结构的体外实验解决了Pur-α解旋酶活性的分子机制。补充在果蝇体内的分析表明，高度保守的苯丙氨酸对Pur-α的解离和神经保护功能的重要性。通过揭示核酸结合的分子机制，本研究有助于理解pur-α的细胞作用及其在神经退行性疾病中的意义。
The neuronal DNA-/RNA-binding protein Pur-alpha is a transcription regulator and core factor for mRNA localization. Pur-alpha-deficient mice die after birth with pleiotropic neuronal defects. Here, we report the crystal structure of the DNA-/RNA-binding domain of Pur-alpha in complex with ssDNA. It reveals base-specific recognition and offers a molecular explanation for the effect of point mutations in the 5q31.3 microdeletion syndrome. Consistent with the crystal structure, biochemical and NMR data indicate that Pur-alpha binds DNA and RNA in the same way, suggesting binding modes for tri- and hexanucleotide-repeat RNAs in two neurodegenerative RNAopathies. Additionally, structure-based in vitro experiments resolved the molecular mechanism of Pur-alpha's unwindase activity. Complementing in vivo analyses in Drosophila demonstrated the importance of a highly conserved phenylalanine for Pur-alpha's unwinding and neuroprotective function. By uncovering the molecular mechanisms of nucleic-acid binding, this study contributes to understanding the cellular role of Pur-alpha and its implications in neurodegenerative diseases.