The P4-P6 domain directs higher order folding of the Tetrahymena ribozyme core
The P4-P6 domain directs higher order folding of the Tetrahymena ribozyme core
复制标题
DOI：
10.1021/bi962428
复制
发表时间：
1997-03-18
期刊：
影响因子：
2.9
通讯作者：
Doudna, JA
中科院分区：
文献类型：
--
作者：
Doherty, EA;Doudna, JA
I组自剪接内含子的活性位点位于两个拟议结构域的界面处。在四膜虫内含子中，催化核心的一半位于独立折叠的P4-P6结构域内，而另一半属于包括螺旋P3、P7、P8和P9（P3-P9）的推定结构域。为了确定内含子的P3-P9区域是否也可以独立折叠，我们使用Fe（II）-EDTA和硫酸二甲酯来探测四膜虫内含子的单独片段的溶剂可及性。这些RNA自组装成反式的活性复合物，从而能够分析它们单独和复合物内的结构特征。我们的研究结果表明，虽然内含子的P3-P9区域保留其二级结构，但在没有P4-P6结构域的情况下，该区域内的大多数三级相互作用不会稳定形成。这表明P4-P6结构域诱导P3-P9区域的折叠，组织它们之间的催化裂缝。因此，P4-P6结构域为四膜虫内含子核心的折叠提供了支架。
The active site of group I self-splicing introns occurs at the interface of two proposed structural domains. In the Tetrahymena intron, half of the catalytic core resides within the independently-folding P4-P6 domain while the other half belongs to a putative domain that includes helices P3, P7, P8, and P9 (P3-P9). To determine whether the P3-P9 region of the intron can also fold independently, we used Fe(II)-EDTA and dimethyl sulfate to probe the solvent accessibility of separate fragments of the Tetrahymena intron. These RNAs self-assemble into an active complex in trans, enabling analysis of their structural features both alone and within the complex. Our results show that while the P3-P9 region of the intron retains its secondary structure, most of the tertiary interactions within this region do not form stably in the absence of the P4-P6 domain. This indicates that the P4-P6 domain induces folding in the P3-P9 region, organizing the catalytic cleft between them. Thus the P4-P6 domain provides a scaffold for the folding of the Tetrahymena intron core.