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| | ==ALTERNATING AND NON-ALTERNATING DG-DC HEXANUCLEOTIDES CRYSTALLIZE AS CANONICAL A-DNA== |
| The line below this paragraph, containing "STRUCTURE_257d", creates the "Structure Box" on the page.
| | <StructureSection load='257d' size='340' side='right'caption='[[257d]], [[Resolution|resolution]] 2.30Å' 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'>[[257d]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=257D OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=257D 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]] 2.3Å</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=257d FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=257d OCA], [https://pdbe.org/257d PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=257d RCSB], [https://www.ebi.ac.uk/pdbsum/257d PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=257d ProSAT]</span></td></tr> |
| {{STRUCTURE_257d| PDB=257d | SCENE= }}
| | </table> |
| | | __TOC__ |
| '''ALTERNATING AND NON-ALTERNATING DG-DC HEXANUCLEOTIDES CRYSTALLIZE AS CANONICAL A-DNA'''
| | </StructureSection> |
| | | [[Category: Large Structures]] |
| | | [[Category: Baxter WW]] |
| ==Overview== | | [[Category: Ho PS]] |
| We have solved the single-crystal X-ray structures of two different hexanucleotides: the alternating sequence d(Gm5CGm5CGC), and the non-alternating sequence d(Gm5CCGGC). Both of these hexamers crystallize readily as A-DNA in the orthorhombic space group C222(1). Although hexanucleotides have been previously crystallized as Z-DNA, and in one case as B-DNA, this is the first time hexanucleotides have been crystallized as A-DNA. Both hexamers adopt a typical A-conformation, which is surprisingly more similar to the structure of A-DNA fibers than to other A-DNA single crystals. The structure of d(Gm5CGm5CGC) was solved to a resolution of 2.1 A (R-factor = 19.6%). This structure has all of the features characteristic of canonical A-DNA, including it's helical repeat (11.2 bp/turn), helical rise (2.6 A/bp), base-pair displacement (-4.7 A), base inclination angle (16.9 degrees), and sugar puckers that are predominantly 3'-endo. The lower resolution, non-alternating structure has similar overall average values for these parameters. We observed several sequence-dependent correlations in these parameters, especially in the d(CG) base step. These steps have lower twist and rise values, coupled with high roll angles as compared to d(GC) steps. The molecular interactions involved in crystal packing and the detailed structure of the bound water in the crystals, however, are similar to those of longer 8 and 10 bp A-DNA crystal structures. Although the structural effect of cytosine methylation on A-DNA appears to be minimal, this modification significantly affects the ability of these sequences to crystallize as A-DNA. In conclusion, we present the A-DNA forming class of hexanucleotides, a new crystallographic system for studying DNA structure at near atomic resolution.
| | [[Category: Mooers BH]] |
| | | [[Category: Schroth GP]] |
| ==About this Structure== | |
| Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=257D OCA]. | |
| | |
| ==Reference== | |
| Alternating and non-alternating dG-dC hexanucleotides crystallize as canonical A-DNA., Mooers BH, Schroth GP, Baxter WW, Ho PS, J Mol Biol. 1995 Jun 16;249(4):772-84. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/7602589 7602589]
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| [[Category: Baxter, W W.]] | |
| [[Category: Ho, P S.]]
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| [[Category: Mooers, B H.]] | |
| [[Category: Schroth, G P.]] | |
| [[Category: A-dna]] | |
| [[Category: Double helix]] | |
| [[Category: Modified]] | |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 18:23:55 2008''
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