View source for 2akg


==Thallium form of the G-Quadruplex from Oxytricha Nova, d(G4T4G4)2==
<StructureSection load='2akg' size='340' side='right'caption='[[2akg]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2akg]] is a 2 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AKG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2AKG 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=2akg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2akg OCA], [https://pdbe.org/2akg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2akg RCSB], [https://www.ebi.ac.uk/pdbsum/2akg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2akg ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Monovalent cations play an important role in many biological functions. The guanine rich sequence, d(G4T4G4), requires monovalent cations for formation of the G-quadruplex, d(G4T4G4)2. This requirement can be satisfied by thallium (Tl+), a potassium (K+) surrogate. To verify that the structure of d(G4T4G4)2 in the presence of Tl+ is similar to the K+-form of the G-quadruplex, the solution structure of the Tl+-form of d(G4T4G4)2 was determined. The 10 lowest energy structures have an all atom RMSD of 0.76 +/- 0.16 A. Comparison of this structure to the identical G-quadruplex formed in the presence of K+ validates the isomorphous nature of Tl+ and K+. Using a 1H-205Tl spin-echo difference experiment we show that, in the Tl+-form of d(G4T4G4)2, small scalar couplings (&lt;1 Hz) exist between 205Tl and protons in the G-quadruplex. These data comprise the first 1H-205Tl scalar couplings observed in a biological system and have the potential to provide important constraints for structure determination. These experiments can be applied to any system in which the substituted Tl+ cations are in slow exchange with the bulk ions in solution.

205Tl NMR methods for the characterization of monovalent cation binding to nucleic acids.,Gill ML, Strobel SA, Loria JP J Am Chem Soc. 2005 Nov 30;127(47):16723-32. PMID:16305263<ref>PMID:16305263</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: Gill ML]]
[[Category: Loria JP]]
[[Category: Strobel SA]]