View source for 1ply


==SODIUM IONS AND WATER MOLECULES IN THE STRUCTURE OF POLY D(A)(DOT)POLY D(T)==
<StructureSection load='1ply' size='340' side='right'caption='[[1ply]], [[Resolution|resolution]] 3.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ply]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PLY OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1PLY FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NA:SODIUM+ION'>NA</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=1ply FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ply OCA], [https://pdbe.org/1ply PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ply RCSB], [https://www.ebi.ac.uk/pdbsum/1ply PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ply ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Analysis of X-ray diffraction data from a polycrystalline and well oriented fiber of the sodium salt of poly(dA).poly(dT) shows that this B'-DNA corresponds to a right-handed antiparallel tenfold double-helix of pitch 32.4 A, with C2'-endo furanose rings in both strands. The helix contrasts itself from B-DNA in terms of a very narrow minor groove. Difference electron-density maps have revealed that a continuous spine of water molecules, two per base pair, propagates along this groove with the same symmetry as the DNA and establishes new links between the two strands. In addition to this hydrated DNA helix, the monoclinic unit cell (space group P2(1)) accommodates about 20 sodium ions and 12 water molecules in the vicinity of phosphate groups. These structured guest molecules provide an intricate network of bridges, ranging in size from a single sodium ion to a multiple sodium-water-water-sodium unit, connecting phosphate groups belonging to adjacent DNA helices. The crystallographic R value for this structure is 0.23 for a total of 102 reflections extending out to 3.2 A resolution.

Sodium ions and water molecules in the structure of poly(dA).poly(dT).,Chandrasekaran R, Radha A, Park HS Acta Crystallogr D Biol Crystallogr. 1995 Nov 1;51(Pt 6):1025-35. PMID:15299771<ref>PMID:15299771</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: Chandrasekaran, R]]
[[Category: Park, H S]]
[[Category: Radha, A]]
[[Category: Dna]]