Mechanism of spliceosome remodeling by the ATPase/helicase Prp2 and its coactivator Spp2
Mechanism of spliceosome remodeling by the ATPase/helicase Prp2 and its coactivator Spp2
复制标题
DOI：
10.1126/science.abe8863
复制
发表时间：
2021-01-08
期刊：
影响因子：
56.9
通讯作者：
Shi, Yigong
中科院分区：
文献类型：
--
作者：
Bai, Rui;Wan, Ruixue;Shi, Yigong
剪接体重塑，由保守的腺苷三磷酸酶（ATP酶）/解旋酶，包括Prp 2，使前体信使RNA（前mRNA）剪接。然而，ATP酶/解旋酶功能的结构基础仍然知之甚少。在这里，我们报告的原子结构的Prp 2隔离，Prp 2与其辅激活剂Spp 2复合，和Prp 2加载激活剪接体和结构导向的生化分析的结果。Prp 2与剪接体弱结合，没有Spp 2就不能发挥作用，Spp 2与Prp 2稳定结合并锚定在剪接体上，从而将Prp 2束缚在激活的剪接体上并允许Prp 2发挥作用。前体mRNA被加载到Prp 2的N和C半部分之间的特征通道中，其中来自N半部分的Leu（536）和来自C半部分的Arg（844）防止前体mRNA向后滑向其5 '端。腺苷5 '-三磷酸结合和水解触发Prp 2中的结构域间移动，其驱动前mRNA向其3'-末端的单向逐步移位。这些保守的机制解释了剪接体重塑与前体mRNA剪接的耦合。
Spliceosome remodeling, executed by conserved adenosine triphosphatase (ATPase)/helicases including Prp2, enables precursor messenger RNA (pre-mRNA) splicing. However, the structural basis for the function of the ATPase/helicases remains poorly understood. Here, we report atomic structures of Prp2 in isolation, Prp2 complexed with its coactivator Spp2, and Prp2-loaded activated spliceosome and the results of structure-guided biochemical analysis. Prp2 weakly associates with the spliceosome and cannot function without Spp2, which stably associates with Prp2 and anchors on the spliceosome, thus tethering Prp2 to the activated spliceosome and allowing Prp2 to function. Pre-mRNA is loaded into a featured channel between the N and C halves of Prp2, where Leu(536) from the N half and Arg(844) from the C half prevent backward sliding of pre-mRNA toward its 5'-end. Adenosine 5'-triphosphate binding and hydrolysis trigger interdomain movement in Prp2, which drives unidirectional stepwise translocation of pre-mRNA toward its 3'-end. These conserved mechanisms explain the coupling of spliceosome remodeling to pre-mRNA splicing.