Interdomain Allostery Promotes Assembly of the Poly(A) mRNA Complex with PABP and eIF4G
Interdomain Allostery Promotes Assembly of the Poly(A) mRNA Complex with PABP and eIF4G
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DOI：
10.1016/j.molcel.2012.09.001
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发表时间：
2012-11-09
期刊：
影响因子：
16
通讯作者：
Gehring, Kalle
中科院分区：
文献类型：
--
作者：
Safaee, Nozhat;Kozlov, Guennadi;Gehring, Kalle
许多RNA结合蛋白含有多个单链核酸结合结构域，并组装成大的多蛋白信使核糖核酸蛋白（mRNP）复合物。这些复合物的自组装机制在很大程度上是未知的。在真核生物中，翻译因子多聚腺苷酸结合蛋白-1（PABP）和eIF 4G的结合对于多聚腺苷酸化mRNA的高水平表达是必不可少的。本文报道了三元配合物poly（A）（11）的晶体结构。PABP（1-190）.eIF4G（178-203），2.0埃分辨率。我们的NMR和晶体学数据表明，eIF 4G与PABP的RRM 2结构域相互作用。通过小角X-射线散射、等温滴定量热法和电迁移率变动分析的相互作用的分析表明，这种相互作用是由聚（A）与PABP结合的变构调节的。此外，我们已经证实了聚（A）的内源性PABP和eIF 4G相互作用的免疫沉淀实验中使用HeLa细胞提取物的重要性。我们的研究结果揭示了域间变构作为合作组装的RNP复合物的机制。
Many RNA-binding proteins contain multiple single-strand nucleic acid-binding domains and assemble into large multiprotein messenger ribonucleic acid protein (mRNP) complexes. The mechanisms underlying the self-assembly of these complexes are largely unknown. In eukaryotes, the association of the translation factors polyadenylate-binding protein-1 (PABP) and eIF4G is essential for high-level expression of polyadenylated mRNAs. Here, we report the crystal structure of the ternary complex poly(A)(11). PABP(1-190).eIF4G(178-203) at 2.0 angstrom resolution. Our NMR and crystallographic data show that eIF4G interacts with the RRM2 domain of PABP. Analysis of the interaction by small-angle X-ray scattering, isothermal titration calorimetry, and electromobility shift assays reveals that this interaction is allosterically regulated by poly(A) binding to PABP. Furthermore, we have confirmed the importance of poly(A) for the endogenous PABP and eIF4G interaction in immunoprecipitation experiments using HeLa cell extracts. Our findings reveal interdomain allostery as a mechanism for cooperative assembly of RNP complexes.