260d

<StructureSection load='260d' size='340' side='right' caption='[[260d]], [[Resolution|resolution]] 1.90&Aring;' scene=''>

<table><tr><td colspan='2'>[[260d]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=260D OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=260D FirstGlance]. <br>

</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=260d FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=260d OCA], [http://pdbe.org/260d PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=260d RCSB], [http://www.ebi.ac.uk/pdbsum/260d PDBsum]</span></td></tr>

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== Publication Abstract from PubMed ==

The crystal structure of the alternating 5'-purine start decamer d(GCGCGCGCGC) was found to be in the left-handed Z-DNA conformation. Inasmuch as the A.T base pair is known to resist Z-DNA formation, we substituted A.T base pairs in the dyad-related positions of the decamer duplex. The alternating self-complementary decamer d(GCACGCGTGC) crystallizes in a different hexagonal space group, P6(1)22, with very different unit cell dimensions a = b = 38.97 and c = 77.34 A compared with the all-G.C alternating decamer. The A.T-containing decamer has one strand in the asymmetric unit, and because it is isomorphous to some other A-DNA decamers it was considered also to be right-handed. The structure was refined, starting with the atomic coordinates of the A-DNA decamer d(GCGGGCCCGC), by use of 2491 unique reflections out to 1.9-A resolution. The refinement converged to an R value of 18.6% for a total of 202 nucleotide atoms and 32 water molecules. This research further demonstrates that A.T base pairs not only resist the formation of Z-DNA but can also assist the formation of A-DNA by switching the helix handedness when the oligomer starts with a 5'-purine; also, the length of the inner Z-DNA stretch (d(CG)n) is reduced from an octamer to a tetramer. It may be noted that these oligonucleotide properties are in crystals and not necessarily in solutions.

Crystal structure of the self-complementary 5'-purine start decamer d(GCACGCGTGC) in the A-DNA conformation. II.,Ban C, Sundaralingam M Biophys J. 1996 Sep;71(3):1222-7. PMID:8873996<ref>PMID:8873996</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 260d" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Ban, C]]

[[Category: Sundaralingam, M]]

[[Category: A-dna]]

[[Category: Double helix]]