7kx9: Difference between revisions
New page: '''Unreleased structure''' The entry 7kx9 is ON HOLD Authors: Description: Category: Unreleased Structures |
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The | ==Cryo-EM structure of Ephydatia fluviatilis PiwiA-piRNA-target complex== | ||
<StructureSection load='7kx9' size='340' side='right'caption='[[7kx9]], [[Resolution|resolution]] 3.50Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[7kx9]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Ephydatia_fluviatilis Ephydatia fluviatilis] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7KX9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7KX9 FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.5Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=OMG:O2-METHYLGUANOSINE-5-MONOPHOSPHATE'>OMG</scene></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=7kx9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7kx9 OCA], [https://pdbe.org/7kx9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7kx9 RCSB], [https://www.ebi.ac.uk/pdbsum/7kx9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7kx9 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/D5MRY8_9METZ D5MRY8_9METZ] | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
PIWI proteins use PIWI-interacting RNAs (piRNAs) to identify and silence transposable elements and thereby maintain genome integrity between metazoan generations(1). The targeting of transposable elements by PIWI has been compared to mRNA target recognition by Argonaute proteins(2,3), which use microRNA (miRNA) guides, but the extent to which piRNAs resemble miRNAs is not known. Here we present cryo-electron microscopy structures of a PIWI-piRNA complex from the sponge Ephydatia fluviatilis with and without target RNAs, and a biochemical analysis of target recognition. Mirroring Argonaute, PIWI identifies targets using the piRNA seed region. However, PIWI creates a much weaker seed so that stable target association requires further piRNA-target pairing, making piRNAs less promiscuous than miRNAs. Beyond the seed, the structure of PIWI facilitates piRNA-target pairing in a manner that is tolerant of mismatches, leading to long-lived PIWI-piRNA-target interactions that may accumulate on transposable-element transcripts. PIWI ensures targeting fidelity by physically blocking the propagation of piRNA-target interactions in the absence of faithful seed pairing, and by requiring an extended piRNA-target duplex to reach an endonucleolytically active conformation. PIWI proteins thereby minimize off-targeting cellular mRNAs while defending against evolving genomic threats. | |||
Structural basis for piRNA targeting.,Anzelon TA, Chowdhury S, Hughes SM, Xiao Y, Lander GC, MacRae IJ Nature. 2021 Sep;597(7875):285-289. doi: 10.1038/s41586-021-03856-x. Epub 2021 , Sep 1. PMID:34471284<ref>PMID:34471284</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
[[Category: | </div> | ||
<div class="pdbe-citations 7kx9" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Ephydatia fluviatilis]] | |||
[[Category: Large Structures]] | |||
[[Category: Synthetic construct]] | |||
[[Category: Anzelon TA]] | |||
[[Category: Chowdhury S]] | |||
[[Category: Lander GC]] | |||
[[Category: MacRae IJ]] | |||
Latest revision as of 22:36, 29 May 2024
Cryo-EM structure of Ephydatia fluviatilis PiwiA-piRNA-target complexCryo-EM structure of Ephydatia fluviatilis PiwiA-piRNA-target complex
Structural highlights
FunctionPublication Abstract from PubMedPIWI proteins use PIWI-interacting RNAs (piRNAs) to identify and silence transposable elements and thereby maintain genome integrity between metazoan generations(1). The targeting of transposable elements by PIWI has been compared to mRNA target recognition by Argonaute proteins(2,3), which use microRNA (miRNA) guides, but the extent to which piRNAs resemble miRNAs is not known. Here we present cryo-electron microscopy structures of a PIWI-piRNA complex from the sponge Ephydatia fluviatilis with and without target RNAs, and a biochemical analysis of target recognition. Mirroring Argonaute, PIWI identifies targets using the piRNA seed region. However, PIWI creates a much weaker seed so that stable target association requires further piRNA-target pairing, making piRNAs less promiscuous than miRNAs. Beyond the seed, the structure of PIWI facilitates piRNA-target pairing in a manner that is tolerant of mismatches, leading to long-lived PIWI-piRNA-target interactions that may accumulate on transposable-element transcripts. PIWI ensures targeting fidelity by physically blocking the propagation of piRNA-target interactions in the absence of faithful seed pairing, and by requiring an extended piRNA-target duplex to reach an endonucleolytically active conformation. PIWI proteins thereby minimize off-targeting cellular mRNAs while defending against evolving genomic threats. Structural basis for piRNA targeting.,Anzelon TA, Chowdhury S, Hughes SM, Xiao Y, Lander GC, MacRae IJ Nature. 2021 Sep;597(7875):285-289. doi: 10.1038/s41586-021-03856-x. Epub 2021 , Sep 1. PMID:34471284[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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