Publication Date:
2009-10-09
Description:
The slicer activity of the RNA-induced silencing complex resides within its Argonaute (Ago) component, in which the PIWI domain provides the catalytic residues governing guide-strand mediated site-specific cleavage of target RNA. Here we report on structures of ternary complexes of Thermus thermophilus Ago catalytic mutants with 5'-phosphorylated 21-nucleotide guide DNA and complementary target RNAs of 12, 15 and 19 nucleotides in length, which define the molecular basis for Mg(2+)-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 the helix requiring the 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 showed the importance of structural and catalytic divalent metal ions observed in the crystal structures.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880917/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880917/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wang, Yanli -- Juranek, Stefan -- Li, Haitao -- Sheng, Gang -- Wardle, Greg S -- Tuschl, Thomas -- Patel, Dinshaw J -- P30 EB009998/EB/NIBIB NIH HHS/ -- R01 AI068776/AI/NIAID NIH HHS/ -- R01 AI068776-04/AI/NIAID NIH HHS/ -- R01 AI068776-05/AI/NIAID NIH HHS/ -- R01 GM068476/GM/NIGMS NIH HHS/ -- R01 GM068476-05/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2009 Oct 8;461(7265):754-61. doi: 10.1038/nature08434.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Structural Biology Program, Memorial-Sloan Kettering Cancer Center, New York, New York 10065, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19812667" target="_blank"〉PubMed〈/a〉
Keywords:
Base Pairing
;
Biocatalysis
;
Catalytic Domain/genetics
;
Cations, Divalent/metabolism
;
Crystallography, X-Ray
;
DNA/chemistry/genetics/metabolism
;
*Gene Silencing
;
Magnesium/metabolism
;
Models, Molecular
;
Phosphorylation
;
RNA/chemistry/genetics/*metabolism
;
RNA-Induced Silencing Complex/*chemistry/genetics/*metabolism
;
Structure-Activity Relationship
;
Substrate Specificity
;
Thermus thermophilus/*enzymology/genetics
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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