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| - | [[Image:1d56.gif|left|200px]] | |
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| - | <!--
| + | ==ALTERNATIVE STRUCTURES FOR ALTERNATING POLY(DA-DT) TRACTS: THE STRUCTURE OF THE B-DNA DECAMER C-G-A-T-A-T-A-T-C-G== |
| - | The line below this paragraph, containing "STRUCTURE_1d56", creates the "Structure Box" on the page.
| + | <StructureSection load='1d56' size='340' side='right'caption='[[1d56]], [[Resolution|resolution]] 1.70Å' 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'>[[1d56]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1D56 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1D56 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]] 1.7Å</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=CA:CALCIUM+ION'>CA</scene></td></tr> |
| - | {{STRUCTURE_1d56| PDB=1d56 | SCENE= }}
| + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1d56 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1d56 OCA], [https://pdbe.org/1d56 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1d56 RCSB], [https://www.ebi.ac.uk/pdbsum/1d56 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1d56 ProSAT]</span></td></tr> |
| - | | + | </table> |
| - | '''ALTERNATIVE STRUCTURES FOR ALTERNATING POLY(DA-DT) TRACTS: THE STRUCTURE OF THE B-DNA DECAMER C-G-A-T-A-T-A-T-C-G'''
| + | __TOC__ |
| - | | + | </StructureSection> |
| - | | + | [[Category: Large Structures]] |
| - | ==Overview== | + | [[Category: Dickerson RE]] |
| - | The X-ray crystal structure of the decamer C-G-A-T-A-T-A-T-C-G has been solved with two contrasting cations, Ca2+ and Mg2+. Crystals with calcium are space group P2(1)2(1)2(1), cell dimensions a = 38.76 A, b = 40.06 A, and c = 33.73 A, and diffract to 1.7-A resolution. Crystals with magnesium have the same space group, cell dimensions a = 38.69 A, b = 39.56 A, and c = 33.64 A, and diffract to 2.0 A. Their structures were solved independently by molecular replacement, beginning with idealized Arnott B-DNA geometry. The calcium structure refined to R = 17.8% for the 3683 reflections greater than 2 sigma, with 404 DNA atoms, 95 solvent peaks, and 1 Ca(H2O)7(2+) ion. The magnesium structure refined to R = 16.5% for the 1852 reflections greater than 2 sigma, with 404 DNA atoms, 62 solvent peaks, and 1 Mg(H2O)6(2+) ion. The two structures are virtually identical and are isostructural with C-G-A-T-C-G-A-T-C-G [Grzeskowiak et al. (1991) J. Biol. Chem. 266, 8861-8883] and C-G-A-T-T-A-A-T-C-G [Quintana et al. (1992) J. Mol. Biol. 225, 375-395]. Comparison of C-G-A-T-A-T-A-T-C-G with C-G-C-A-T-A-T-A-T-G-C-G [Yoon et al. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 6332-6336] shows that the expected alternation of twist angles is found in the central A-T-A-T-A-T region of the decamer (A-T small, T-A large), but the minor groove remains wide at the center, rather than narrow. Minor groove narrowing is produced, in these two structures, not by overwinding of the helix, but by an increase in base pair propeller. This analysis confirms the concept that poly(dA-dT).poly(dA-dT) is polymorphous, with different local conformations possible in different local environments.
| + | [[Category: Quintana J]] |
| - | | + | [[Category: Yuan H]] |
| - | ==About this Structure== | + | |
| - | Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1D56 OCA].
| + | |
| - | | + | |
| - | ==Reference==
| + | |
| - | Alternative structures for alternating poly(dA-dT) tracts: the structure of the B-DNA decamer C-G-A-T-A-T-A-T-C-G., Yuan H, Quintana J, Dickerson RE, Biochemistry. 1992 Sep 1;31(34):8009-21. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/1510987 1510987]
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| - | [[Category: Dickerson, R E.]] | + | |
| - | [[Category: Quintana, J.]] | + | |
| - | [[Category: Yuan, H.]] | + | |
| - | [[Category: B-dna]] | + | |
| - | [[Category: Double helix]] | + | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 13:27:49 2008''
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