225d: Difference between revisions
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== | ==A TETRAMERIC DNA STRUCTURE WITH PROTONATED CYTOSINE:CYTOSINE BASE PAIRS== | ||
<StructureSection load='225d' size='340' side='right'caption='[[225d]]' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[225d]] is a 4 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=225D OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=225D 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=225d FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=225d OCA], [https://pdbe.org/225d PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=225d RCSB], [https://www.ebi.ac.uk/pdbsum/225d PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=225d ProSAT]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Oligomers containing tracts of cytidine form hemiprotonated base pairs at acid pH and have been considered to be double-stranded. We have solved the structure of the DNA oligomer 5'-d(TCCCCC) at acid pH and find that it is a four-stranded complex in which two base-paired parallel-stranded duplexes are intimately associated, with their base pairs fully intercalated. The relative orientation of the duplexes is antiparallel, so that each base pair is face-to-face with its neighbours. The NMR spectrum displays only six spin systems, showing that the structure is highly symmetrical on the NMR timescale; the four strands are equivalent. A model derived by energy minimization and constrained molecular dynamics shows excellent compatibility with the observed nuclear Overhauser effects (NOEs) particularly for the very unusual inter-residue sugar-sugar NOEs H1'-H1', H1'-H2" and H1'-H4'. These NOEs are probably diagnostic for such tetrameric structures. | Oligomers containing tracts of cytidine form hemiprotonated base pairs at acid pH and have been considered to be double-stranded. We have solved the structure of the DNA oligomer 5'-d(TCCCCC) at acid pH and find that it is a four-stranded complex in which two base-paired parallel-stranded duplexes are intimately associated, with their base pairs fully intercalated. The relative orientation of the duplexes is antiparallel, so that each base pair is face-to-face with its neighbours. The NMR spectrum displays only six spin systems, showing that the structure is highly symmetrical on the NMR timescale; the four strands are equivalent. A model derived by energy minimization and constrained molecular dynamics shows excellent compatibility with the observed nuclear Overhauser effects (NOEs) particularly for the very unusual inter-residue sugar-sugar NOEs H1'-H1', H1'-H2" and H1'-H4'. These NOEs are probably diagnostic for such tetrameric structures. | ||
A tetrameric DNA structure with protonated cytosine.cytosine base pairs.,Gehring K, Leroy JL, Gueron M Nature. 1993 Jun 10;363(6429):561-5. PMID:8389423<ref>PMID:8389423</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
[[Category: | <div class="pdbe-citations 225d" style="background-color:#fffaf0;"></div> | ||
[[Category: Gehring | == References == | ||
[[Category: Gueron | <references/> | ||
[[Category: Leroy | __TOC__ | ||
</StructureSection> | |||
[[Category: Large Structures]] | |||
[[Category: Gehring K]] | |||
[[Category: Gueron M]] | |||
[[Category: Leroy JL]] | |||
Latest revision as of 16:31, 13 December 2023
A TETRAMERIC DNA STRUCTURE WITH PROTONATED CYTOSINE:CYTOSINE BASE PAIRS
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