Nucleation, propagation and cleavage of target RNAs in Ago silencing complexes.
Nucleation, propagation and cleavage of target RNAs in Ago silencing complexes.
复制标题
作者：
RNA诱导的沉默复合物的切割活性存在于其Argonaute（Ago）组分内，其PIWI结构域提供了控制引导链介导的靶RNA的位点特异性切割的催化残基。本文报道了T.嗜热Ago催化突变体具有5′-磷酸化的21-nt引导DNA和长度为12-、15-和19-nt的互补靶RNA，其定义了Mg 2+促进的靶位点特异性切割的分子基础。我们观察到Ago支架内从成核到导向-靶双链体形成的传播步骤的类似于Bicht-like结构域的运动，双链体拉链超过一圈螺旋，需要从PAZ口袋释放导向的3′-末端。对各种长度的靶的切割测定支持该模型，并且糖-磷酸骨架修饰的靶链揭示了在晶体结构中观察到的结构和催化二价金属离子的重要性。
The slicer activity of the RNA-induced silencing complex resides within its Argonaute (Ago) component, whose PIWI domain provides the catalytic residues governing guide-strand mediated site-specific cleavage of target RNA. We report on structures of ternary complexes of T. thermophilus Ago catalytic mutants with 5′-phosphorylated 21-nt guide DNA and complementary target RNAs of length 12-, 15- and 19-nt, which define the molecular basis for Mg2+-facilitated site-specific cleavage of the target. We observe pivot-like domain movements within the Ago scaffold on proceeding from nucleation to propagation steps of guide-target duplex formation, with duplex zippering beyond one turn of helix requiring release of the 3′-end of the guide from the PAZ pocket. Cleavage assays on targets of various lengths supported this model, and sugar-phosphate backbone modified target strands revealed the importance of structural and catalytic divalent metal ions observed in the crystal structures.
登录
查看更多内容
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
64.8
作者：
Castanotto, Daniela;Rossi, John J.
通讯作者：
Rossi, John J.
DOI：
10.1038/nrd2310
发表时间：
2007-06
期刊：
Nature reviews. Drug discovery
影响因子：
--
作者：
de Fougerolles A;Vornlocher HP;Maraganore J;Lieberman J
通讯作者：
Lieberman J
DOI：
10.1107/s0907444998003254
发表时间：
1998-09-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
--
作者：
Brunger, AT;Adams, PD;Warren, GL
通讯作者：
Warren, GL
影响因子：
64.5
作者：
Mi, Shijun;Cai, Tao;Qi, Yijun
通讯作者：
Qi, Yijun