View source for 3npn


==Structure of the s-adenosylhomocysteine riboswitch at 3.0A==
<StructureSection load='3npn' size='340' side='right'caption='[[3npn]], [[Resolution|resolution]] 2.79&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3npn]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Ralstonia_solanacearum Ralstonia solanacearum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3NPN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3NPN FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.792&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</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=3npn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3npn OCA], [https://pdbe.org/3npn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3npn RCSB], [https://www.ebi.ac.uk/pdbsum/3npn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3npn ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
S-adenosyl-(L)-homocysteine (SAH) riboswitches are regulatory elements found in bacterial mRNAs that up-regulate genes involved in the S-adenosyl-(L)-methionine (SAM) regeneration cycle. To understand the structural basis of SAH-dependent regulation by RNA, we have solved the structure of its metabolite-binding domain in complex with SAH. This structure reveals an unusual pseudoknot topology that creates a shallow groove on the surface of the RNA that binds SAH primarily through interactions with the adenine ring and methionine main chain atoms and discriminates against SAM through a steric mechanism. Chemical probing and calorimetric analysis indicate that the unliganded RNA can access bound-like conformations that are significantly stabilized by SAH to direct folding of the downstream regulatory switch. Strikingly, we find that metabolites bearing an adenine ring, including ATP, bind this aptamer with sufficiently high affinity such that normal intracellular concentrations of these compounds may influence regulation of the riboswitch.

Structural basis for recognition of S-adenosylhomocysteine by riboswitches.,Edwards AL, Reyes FE, Heroux A, Batey RT RNA. 2010 Sep 23. PMID:20864509<ref>PMID:20864509</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 3npn" style="background-color:#fffaf0;"></div>

==See Also==
*[[Riboswitch 3D structures|Riboswitch 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Ralstonia solanacearum]]
[[Category: Batey RT]]
[[Category: Edwards AE]]
[[Category: Reyes FE]]