View source for 3iqn


==Free-state structural transitions of the SAM-I riboswitch==
<StructureSection load='3iqn' size='340' side='right'caption='[[3iqn]], [[Resolution|resolution]] 2.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3iqn]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3IQN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3IQN 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]] 2.7&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BA:BARIUM+ION'>BA</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=SAM:S-ADENOSYLMETHIONINE'>SAM</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=3iqn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3iqn OCA], [https://pdbe.org/3iqn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3iqn RCSB], [https://www.ebi.ac.uk/pdbsum/3iqn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3iqn ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Riboswitches are highly structured elements residing in the 5' untranslated region of messenger RNAs that specifically bind cellular metabolites to alter gene expression. While there are many structures of ligand-bound riboswitches that reveal details of bimolecular recognition, their unliganded structures remain poorly characterized. Characterizing the molecular details of the unliganded state is crucial for understanding the riboswitch's mechanism of action because it is this state that actively interrogates the cellular environment and helps direct the regulatory outcome. To develop a detailed description of the ligand-free form of an S-adenosylmethionine binding riboswitch at the local and global levels, we have employed a series of biochemical, biophysical, and computational methods. Our data reveal that the ligand binding domain adopts an ensemble of states that minimizes the energy barrier between the free and bound states to establish an efficient decision making branchpoint in the regulatory process.

Free state conformational sampling of the SAM-I riboswitch aptamer domain.,Stoddard CD, Montange RK, Hennelly SP, Rambo RP, Sanbonmatsu KY, Batey RT Structure. 2010 Jul 14;18(7):787-97. PMID:20637415<ref>PMID:20637415</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 3iqn" style="background-color:#fffaf0;"></div>

==See Also==
*[[Riboswitch 3D structures|Riboswitch 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Batey RT]]
[[Category: Montange RK]]