View source for 7xsk


==Misfolded Tetrahymena ribozyme conformation 1==
<StructureSection load='7xsk' size='340' side='right'caption='[[7xsk]], [[Resolution|resolution]] 3.53&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7xsk]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Tetrahymena_thermophila Tetrahymena thermophila]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7XSK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7XSK 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]] 3.53&#8491;</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=7xsk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7xsk OCA], [https://pdbe.org/7xsk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7xsk RCSB], [https://www.ebi.ac.uk/pdbsum/7xsk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7xsk ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The Tetrahymena group I intron has been a key system in the understanding of RNA folding and misfolding. The molecule folds into a long-lived misfolded intermediate (M) in vitro, which has been known to form extensive native-like secondary and tertiary structures but is separated by an unknown kinetic barrier from the native state (N). Here, we used cryogenic electron microscopy (cryo-EM) to resolve misfolded structures of the Tetrahymena L-21 ScaI ribozyme. Maps of three M substates (M1, M2, M3) and one N state were achieved from a single specimen with overall resolutions of 3.5 A, 3.8 A, 4.0 A, and 3.0 A, respectively. Comparisons of the structures reveal that all the M substates are highly similar to N, except for rotation of a core helix P7 that harbors the ribozyme's guanosine binding site and the crossing of the strands J7/3 and J8/7 that connect P7 to the other elements in the ribozyme core. This topological difference between the M substates and N state explains the failure of 5'-splice site substrate docking in M, supports a topological isomer model for the slow refolding of M to N due to a trapped strand crossing, and suggests pathways for M-to-N refolding.

Topological crossing in the misfolded Tetrahymena ribozyme resolved by cryo-EM.,Li S, Palo MZ, Pintilie G, Zhang X, Su Z, Kappel K, Chiu W, Zhang K, Das R Proc Natl Acad Sci U S A. 2022 Sep 13;119(37):e2209146119. doi: , 10.1073/pnas.2209146119. Epub 2022 Sep 6. PMID:36067294<ref>PMID:36067294</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 7xsk" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ribozyme 3D structures|Ribozyme 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Tetrahymena thermophila]]
[[Category: Chiu W]]
[[Category: Das R]]
[[Category: Kappel K]]
[[Category: Li S]]
[[Category: Palo M]]
[[Category: Pintilie G]]
[[Category: Su Z]]
[[Category: Zhang K]]
[[Category: Zhang X]]