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| [[Image:1d87.gif|left|200px]]<br /><applet load="1d87" size="450" color="white" frame="true" align="right" spinBox="true"
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| caption="1d87, resolution 2.250Å" />
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| '''CONFORMATIONAL INFLUENCE OF THE RIBOSE 2'-HYDROXYL GROUP: CRYSTAL STRUCTURES OF DNA-RNA CHIMERIC DUPLEXES'''<br />
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| ==Overview== | | ==CONFORMATIONAL INFLUENCE OF THE RIBOSE 2'-HYDROXYL GROUP: CRYSTAL STRUCTURES OF DNA-RNA CHIMERIC DUPLEXES== |
| We have crystallized three double-helical DNA-RNA chimeric duplexes and, determined their structures by X-ray crystallography at resolutions, between 2 and 2.25 A. The two self-complementary duplexes, [r(G)d(CGTATACGC)]2 and [d(GCGT)r(A)d(TACGC)]2, as well as the Okazaki, fragment d(GGGTATACGC).r(GCG)d(TATACCC), were found to adopt A-type, conformations. The crystal structures are non-isomorphous, and the, crystallographic environments for the three chimeras are different. A, number of intramolecular interactions of the ribose 2'-hydroxyl groups, contribute to the stabilization of the A-conformation. Hydrogen bonds, between 2'-hydroxyls and 5'-oxygens or phosphate oxygens, in addition to, the previously observed hydrogen bonds to 1'-oxygens of adjacent riboses, and deoxyriboses, are observed in the DNA-RNA chimeric duplexes. The, crystalline chimeric duplexes do not show a transition between the DNA A-, and B-conformations. CD spectra suggest that the Okazaki fragment assumes, an A-conformation in solution as well. In this molecule the three RNA, residues may therefore lock the complete decamer in the A-conformation., Crystals of an all-DNA strand with the same sequence as the, self-complementary chimeras show a morphology which is different from, those of the chimera crystals. Moreover, the oligonucleotide does not, match any of the sequence characteristics of DNAs usually adopting the, A-conformation in the crystalline state (e.g., octamers with short, alternating stretches of purines and pyrimidines). In DNA-RNA chimeric, duplexes, it is therefore possible that a single RNA residue can drive the, conformational equilibrium toward the A-conformation.
| | <StructureSection load='1d87' size='340' side='right'caption='[[1d87]], [[Resolution|resolution]] 2.25Å' scene=''> |
| | | == Structural highlights == |
| ==About this Structure== | | <table><tr><td colspan='2'>[[1d87]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1D87 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1D87 FirstGlance]. <br> |
| 1D87 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1D87 OCA].
| | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.25Å</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=1d87 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1d87 OCA], [https://pdbe.org/1d87 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1d87 RCSB], [https://www.ebi.ac.uk/pdbsum/1d87 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1d87 ProSAT]</span></td></tr> |
| ==Reference==
| | </table> |
| Conformational influence of the ribose 2'-hydroxyl group: crystal structures of DNA-RNA chimeric duplexes., Egli M, Usman N, Rich A, Biochemistry. 1993 Apr 6;32(13):3221-37. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=7681688 7681688]
| | __TOC__ |
| [[Category: Protein complex]] | | </StructureSection> |
| [[Category: Egli, M.]] | | [[Category: Large Structures]] |
| [[Category: Rich, A.]] | | [[Category: Egli M]] |
| [[Category: Usman, N.]] | | [[Category: Rich A]] |
| [[Category: a-dna/rna]]
| | [[Category: Usman N]] |
| [[Category: double helix]]
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| ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Sun Nov 25 02:44:09 2007''
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