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==Structure of stacked G-quadruplex formed by human TERRA sequence in potassium solution==
<StructureSection load='2m18' size='340' side='right'caption='[[2m18]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2m18]] is a 4 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2M18 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2M18 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</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=2m18 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2m18 OCA], [https://pdbe.org/2m18 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2m18 RCSB], [https://www.ebi.ac.uk/pdbsum/2m18 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2m18 ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Telomeric repeat-containing RNAs (TERRA) are transcription products of the telomeres. Human TERRA sequences containing UUAGGG repeats can form parallel-stranded G-quadruplexes. The stacking interaction of such structures was shown to be important for ligand targeting and higher-order arrangement of G-quadruplexes in long TERRA sequences. Here we report on the first high-resolution structure of a stacked G-quadruplex formed by the 10-nucleotide human TERRA sequence r(GGGUUAGGGU) in potassium solution. This structure comprises two dimeric three-layer parallel-stranded G-quadruplex blocks, which stack on each other at their 5'-ends. The adenine in each UUA loop is nearly coplanar with the 5'-end G-tetrad forming an A.(G.G.G.G).A hexad, thereby increasing the stacking contacts between the two blocks. Interestingly, this stacking and loop conformation is different from all structures previously reported for the free human TERRA but resembles the structure previously determined for a complex between a human TERRA sequence and an acridine ligand. This stacking conformation is a potential target for drugs that recognize or induce the stacking interface.

Structure of Human Telomeric RNA (TERRA): Stacking of Two G-Quadruplex Blocks in K(+) Solution.,Martadinata H, Phan AT Biochemistry. 2013 Apr 2;52(13):2176-83. doi: 10.1021/bi301606u. Epub 2013 Mar, 19. PMID:23445442<ref>PMID:23445442</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Martadinata H]]
[[Category: Phan AT]]