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| <!--
| | ==Cobalt hexammine induced tautomeric shift in Z-DNA: the structure of d(CGCGCA).d(TGCGCG) in two crystal forms== |
| The line below this paragraph, containing "STRUCTURE_1xa2", creates the "Structure Box" on the page.
| | <StructureSection load='1xa2' size='340' side='right'caption='[[1xa2]], [[Resolution|resolution]] 1.71Å' scene=''> |
| You may change the PDB parameter (which sets the PDB file loaded into the applet)
| | == Structural highlights == |
| or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
| | <table><tr><td colspan='2'>[[1xa2]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XA2 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1XA2 FirstGlance]. <br> |
| or leave the SCENE parameter empty for the default display.
| | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.71Å</td></tr> |
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| | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NCO:COBALT+HEXAMMINE(III)'>NCO</scene></td></tr> |
| {{STRUCTURE_1xa2| PDB=1xa2 | SCENE= }}
| | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1xa2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xa2 OCA], [https://pdbe.org/1xa2 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1xa2 RCSB], [https://www.ebi.ac.uk/pdbsum/1xa2 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1xa2 ProSAT]</span></td></tr> |
| | | </table> |
| '''Cobalt hexammine induced tautomeric shift in Z-DNA: the structure of d(CGCGCA).d(TGCGCG) in two crystal forms'''
| | __TOC__ |
| | | </StructureSection> |
| | | [[Category: Large Structures]] |
| ==Overview== | | [[Category: Gautham N]] |
| We report here the crystal structure of the DNA hexamer duplex d(CGCGCA)*d(TGCGCG) at 1.71 A resolution. The crystals, in orthorhombic space group, were grown in the presence of cobalt hexammine, a known inducer of the left-handed Z form of DNA. The interaction of this ion with the DNA helix results in a change of the adenine base from the common amino tautomeric form to the imino tautomer. Consequently the A:T base pair is disrupted from the normal Watson-Crick base pairing to a 'wobble' like base pairing. This change is accommodated easily within the helix, and the helical parameters are those expected for Z-DNA. When the cobalt hexammine concentration is decreased slightly in the crystallization conditions, the duplex crystallizes in a different, hexagonal space group, with two hexamer duplexes in the asymmetric unit. One of these is situated on a crystallographic 6-fold screw axis, leading to disorder. The tautomeric shift is not observed in this space group. We show that the change in inter-helix interactions that lead to the two different space groups probably arise from the small decrease in ion concentration, and consequently disordered positions for the ion.
| | [[Category: Rajan SS]] |
| | | [[Category: Thiyagarajan S]] |
| ==About this Structure== | |
| Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XA2 OCA]. | |
| | |
| ==Reference== | |
| Cobalt hexammine induced tautomeric shift in Z-DNA: the structure of d(CGCGCA)*d(TGCGCG) in two crystal forms., Thiyagarajan S, Rajan SS, Gautham N, Nucleic Acids Res. 2004 Nov 8;32(19):5945-53. Print 2004. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/15534365 15534365]
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| [[Category: Gautham, N.]] | |
| [[Category: Rajan, S S.]] | |
| [[Category: Thiyagarajan, S.]] | |
| [[Category: Double helix]] | |
| [[Category: Z-dna]] | |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 14:46:02 2008''
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