Structural basis for RNA-duplex recognition and unwinding by the DEAD-box helicase Mss116p.
Structural basis for RNA-duplex recognition and unwinding by the DEAD-box helicase Mss116p.
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DOI：
10.1038/nature11402
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发表时间：
2012-10-04
期刊：
影响因子：
64.8
通讯作者：
Lambowitz, Alan M.
中科院分区：
文献类型：
--
作者：
Mallam, Anna L.;Del Campo, Mark;Gilman, Benjamin;Sidote, David J.;Lambowitz, Alan M.
DEAD-box蛋白是最大的核酸解旋酶家族，对生命所有领域的RNA代谢都至关重要。它们含有两个reca样结构域的保守“解旋酶核心”（结构域1和2；分别为D1和D2），该结构域利用ATP通过非过程的局部链分离催化短RNA双链的解绕。这种作用模式不同于易位解旋酶，允许DEAD-box蛋白在不破坏RNA结构的情况下重塑大RNA和RNA-蛋白复合物。然而，这种独特的rna解绕模式的结构基础仍不清楚。酵母DEAD-box蛋白Mss116p的结构、生化和遗传分析表明，解旋酶核心结构域具有模块化功能，能够实现RNA双工识别和解绕的新机制。通过单独和共同研究D1和D2，我们发现D1作为atp结合结构域，D2作为rna双工识别结构域。D2含有一个由保守的DEAD-box蛋白序列基序形成的核酸结合袋，可容纳a型而非b型双链，为RNA底物特异性提供了基础。在构象变化中，两个核心结构域与atp酶活性位点连接形成“封闭状态”，D1中的保守基序通过排除一条RNA链和弯曲另一条RNA链来促进与D2结合的双底物的解绕。我们的研究结果为DEAD-box蛋白如何识别和解开RNA双链提供了一个全面的结构模型。该模型解释了DEAD-box蛋白功能的关键特征，并为其他RNA和DNA解旋酶的进化相关核心如何分化使用不同的机制提供了新的视角。
DEAD-box proteins are the largest family of nucleic acid helicases and are crucial to RNA metabolism throughout all domains of life. They contain a conserved ‘helicase core’ of two RecA-like domains (domains 1 and 2; D1 and D2, respectively), which uses ATP to catalyze the unwinding of short RNA duplexes by nonprocessive, local strand separation. This mode of action differs from that of translocating helicases and allows DEAD-box proteins to remodel large RNAs and RNA-protein complexes without globally disrupting RNA structure. However, the structural basis for this distinctive mode of RNA-unwinding remains unclear. Here, structural, biochemical, and genetic analyses of the yeast DEAD-box protein Mss116p indicate that the helicase core domains have modular functions that enable a novel mechanism for RNA duplex recognition and unwinding. By investigating D1 and D2 individually and together, we find that D1 acts as an ATP-binding domain and D2 functions as an RNA-duplex recognition domain. D2 contains a nucleic acid-binding pocket that is formed by conserved DEAD-box protein sequence motifs and accommodates A-form but not B-form duplexes, providing a basis for RNA substrate specificity. Upon a conformational change in which the two core domains join to form a ‘closed-state’ with an ATPase active site, conserved motifs in D1 promote the unwinding of duplex substrates bound to D2 by excluding one RNA strand and bending the other. Our results provide a comprehensive structural model for how DEAD-box proteins recognize and unwind RNA duplexes. This model explains key features of DEAD-box protein function and affords new perspective on how the evolutionarily related cores of other RNA and DNA helicases diverged to use different mechanisms.
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影响因子：
64.8
作者：
Jiang, Fuguo;Ramanathan, Anand;Miller, Matthew T.;Tang, Guo-Qing;Gale, Michael, Jr.;Patel, Smita S.;Marcotrigiano, Joseph
通讯作者：
Marcotrigiano, Joseph
DOI：
10.1107/s0907444905036693
发表时间：
2006-01-01
影响因子：
2.2
作者：
Evans, P
通讯作者：
Evans, P
影响因子：
14.9
作者：
Gorbalenya AE;Koonin EV;Donchenko AP;Blinov VM
通讯作者：
Blinov VM
DOI：
10.1073/pnas.0407896101
发表时间：
2005-01-04
影响因子：
11.1
作者：
Huang, HR;Rowe, CE;Perlman, PS
通讯作者：
Perlman, PS
影响因子：
7.3
作者：
Jarmoskaite, Inga;Russell, Rick
通讯作者：
Russell, Rick