View source for 1mdg


==An Alternating Antiparallel Octaplex in an RNA Crystal Structure==
<StructureSection load='1mdg' size='340' side='right'caption='[[1mdg]], [[Resolution|resolution]] 1.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1mdg]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MDG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1MDG 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]] 1.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BGM:8-BROMO-2-DEOXYGUANOSINE-5-MONOPHOSPHATE'>BGM</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=NCO:COBALT+HEXAMMINE(III)'>NCO</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=1mdg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mdg OCA], [https://pdbe.org/1mdg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1mdg RCSB], [https://www.ebi.ac.uk/pdbsum/1mdg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1mdg ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Multistranded helical structures in nucleic acids play various functions in biological processes. Here we report the crystal structure of a hexamer, rU(BrdG)r(AGGU),at 1.5 A resolution containing a structural complex of an alternating antiparallel eight-stranded helical fragment that is sandwiched in two tetraplexes. The octaplex is formed by groove binding interaction and base tetrad intercalation between two tetraplexes. Two different forms of octaplexes have been proposed, which display different properties in interaction with proteins and nucleic acids. Adenines form a base tetrad in the novel N6-H em leader N3 conformation and further interact with uridines to form an adenine-uridine octad in the reverse Hoogsteen pairing scheme. The conformational flexibility of adenine tetrad indicates that it can optimize its conformation in different interactions.

An eight-stranded helical fragment in RNA crystal structure: implications for tetraplex interaction.,Pan B, Xiong Y, Shi K, Sundaralingam M Structure. 2003 Jul;11(7):825-31. PMID:12842045<ref>PMID:12842045</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1mdg" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Pan BC]]
[[Category: Shi K]]
[[Category: Sundaralingam M]]
[[Category: Xiong Y]]