4w5t: Difference between revisions
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==The Crystal Structure of Human Argonaute2 Bound to a Guide and Target RNA Containing Seed Pairing from 2-7== | ==The Crystal Structure of Human Argonaute2 Bound to a Guide and Target RNA Containing Seed Pairing from 2-7== | ||
<StructureSection load='4w5t' size='340' side='right' caption='[[4w5t]], [[Resolution|resolution]] 2.50Å' scene=''> | <StructureSection load='4w5t' size='340' side='right' caption='[[4w5t]], [[Resolution|resolution]] 2.50Å' scene=''> | ||
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</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=IPH:PHENOL'>IPH</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr> | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=IPH:PHENOL'>IPH</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr> | ||
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4w5n|4w5n]], [[4w5o|4w5o]], [[4w5q|4w5q]], [[4w5r|4w5r]]</td></tr> | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4w5n|4w5n]], [[4w5o|4w5o]], [[4w5q|4w5q]], [[4w5r|4w5r]]</td></tr> | ||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4w5t FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4w5t OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4w5t RCSB], [http://www.ebi.ac.uk/pdbsum/4w5t PDBsum]</span></td></tr> | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4w5t FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4w5t OCA], [http://pdbe.org/4w5t PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4w5t RCSB], [http://www.ebi.ac.uk/pdbsum/4w5t PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4w5t ProSAT]</span></td></tr> | ||
</table> | </table> | ||
== Function == | == Function == | ||
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
</div> | </div> | ||
<div class="pdbe-citations 4w5t" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Argonaute|Argonaute]] | |||
== References == | == References == | ||
<references/> | <references/> |
Revision as of 01:36, 6 August 2016
The Crystal Structure of Human Argonaute2 Bound to a Guide and Target RNA Containing Seed Pairing from 2-7The Crystal Structure of Human Argonaute2 Bound to a Guide and Target RNA Containing Seed Pairing from 2-7
Structural highlights
Function[AGO2_HUMAN] Required for RNA-mediated gene silencing (RNAi) by the RNA-induced silencing complex (RISC). The 'minimal RISC' appears to include EIF2C2/AGO2 bound to a short guide RNA such as a microRNA (miRNA) or short interfering RNA (siRNA). These guide RNAs direct RISC to complementary mRNAs that are targets for RISC-mediated gene silencing. The precise mechanism of gene silencing depends on the degree of complementarity between the miRNA or siRNA and its target. Binding of RISC to a perfectly complementary mRNA generally results in silencing due to endonucleolytic cleavage of the mRNA specifically by EIF2C2/AGO2. Binding of RISC to a partially complementary mRNA results in silencing through inhibition of translation, and this is independent of endonuclease activity. May inhibit translation initiation by binding to the 7-methylguanosine cap, thereby preventing the recruitment of the translation initiation factor eIF4-E. May also inhibit translation initiation via interaction with EIF6, which itself binds to the 60S ribosomal subunit and prevents its association with the 40S ribosomal subunit. The inhibition of translational initiation leads to the accumulation of the affected mRNA in cytoplasmic processing bodies (P-bodies), where mRNA degradation may subsequently occur. In some cases RISC-mediated translational repression is also observed for miRNAs that perfectly match the 3' untranslated region (3'-UTR). Can also up-regulate the translation of specific mRNAs under certain growth conditions. Binds to the AU element of the 3'-UTR of the TNF (TNF-alpha) mRNA and up-regulates translation under conditions of serum starvation. Also required for transcriptional gene silencing (TGS), in which short RNAs known as antigene RNAs or agRNAs direct the transcriptional repression of complementary promoter regions.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] Publication Abstract from PubMedMicroRNAs (miRNAs) control expression of thousands of genes in plants and animals. miRNAs function by guiding Argonaute proteins to complementary sites in messenger RNAs (mRNAs) targeted for repression. We determined crystal structures of human Argonaute-2 (Ago2) bound to a defined guide RNA with and without target RNAs representing miRNA recognition sites. These structures suggest a stepwise mechanism, in which Ago2 primarily exposes guide nucleotides (nt) 2 to 5 for initial target pairing. Pairing to nt 2 to 5 promotes conformational changes that expose nt 2 to 8 and 13 to 16 for further target recognition. Interactions with the guide-target minor groove allow Ago2 to interrogate target RNAs in a sequence-independent manner, whereas an adenosine binding-pocket opposite guide nt 1 further facilitates target recognition. Spurious slicing of miRNA targets is avoided through an inhibitory coordination of one catalytic magnesium ion. These results explain the conserved nucleotide-pairing patterns in animal miRNA target sites first observed over two decades ago. Gene regulation. Structural basis for microRNA targeting.,Schirle NT, Sheu-Gruttadauria J, MacRae IJ Science. 2014 Oct 31;346(6209):608-13. doi: 10.1126/science.1258040. PMID:25359968[23] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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