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==Crystal Structure of the Twister Ribozyme with the Nucleotide 5'- to the Cleavage Site Ordered at 4.1 A Resolution==
<StructureSection load='4qjh' size='340' side='right'caption='[[4qjh]], [[Resolution|resolution]] 3.88&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4qjh]] is a 6 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4QJH OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4QJH FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GTP:GUANOSINE-5-TRIPHOSPHATE'>GTP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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=4qjh FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4qjh OCA], [https://pdbe.org/4qjh PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4qjh RCSB], [https://www.ebi.ac.uk/pdbsum/4qjh PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4qjh ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Twister is a recently discovered RNA motif that is estimated to have one of the fastest known catalytic rates of any naturally occurring small self-cleaving ribozyme. We determined the 4.1-A resolution crystal structure of a twister sequence from an organism that has not been cultured in isolation, and it shows an ordered scissile phosphate and nucleotide 5' to the cleavage site. A second crystal structure of twister from Orzyza sativa determined at 3.1-A resolution exhibits a disordered scissile phosphate and nucleotide 5' to the cleavage site. The core of twister is stabilized by base pairing, a large network of stacking interactions, and two pseudoknots. We observe three nucleotides that appear to mediate catalysis: a guanosine that we propose deprotonates the 2'-hydroxyl of the nucleotide 5' to the cleavage site and a conserved adenosine. We suggest the adenosine neutralizes the negative charge on a nonbridging phosphate oxygen atom at the cleavage site. The active site also positions the labile linkage for in-line nucleophilic attack, and thus twister appears to simultaneously use three strategies proposed for small self-cleaving ribozymes. The twister crystal structures (i) show its global structure, (ii) demonstrate the significance of the double pseudoknot fold, (iii) provide a possible hypothesis for enhanced catalysis, and (iv) illuminate the roles of all 10 highly conserved nucleotides of twister that participate in the formation of its small and stable catalytic pocket.

Structural basis for the fast self-cleavage reaction catalyzed by the twister ribozyme.,Eiler D, Wang J, Steitz TA Proc Natl Acad Sci U S A. 2014 Aug 25. pii: 201414571. PMID:25157168<ref>PMID:25157168</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 4qjh" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ribozyme 3D structures|Ribozyme 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Eiler DR]]
[[Category: Steitz TA]]
[[Category: Wang J]]