1d87: Difference between revisions
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'''CONFORMATIONAL INFLUENCE OF THE RIBOSE 2'-HYDROXYL GROUP: CRYSTAL STRUCTURES OF DNA-RNA CHIMERIC DUPLEXES''' | '''CONFORMATIONAL INFLUENCE OF THE RIBOSE 2'-HYDROXYL GROUP: CRYSTAL STRUCTURES OF DNA-RNA CHIMERIC DUPLEXES''' | ||
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==About this Structure== | ==About this Structure== | ||
Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1D87 OCA]. | |||
==Reference== | ==Reference== | ||
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://www.ncbi.nlm.nih.gov/pubmed/7681688 7681688] | 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://www.ncbi.nlm.nih.gov/pubmed/7681688 7681688] | ||
[[Category: Egli, M.]] | [[Category: Egli, M.]] | ||
[[Category: Rich, A.]] | [[Category: Rich, A.]] | ||
[[Category: Usman, N.]] | [[Category: Usman, N.]] | ||
[[Category: | [[Category: A-dna/rna]] | ||
[[Category: | [[Category: Double helix]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 13:33:30 2008'' | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | |||
Revision as of 10:33, 2 May 2008
CONFORMATIONAL INFLUENCE OF THE RIBOSE 2'-HYDROXYL GROUP: CRYSTAL STRUCTURES OF DNA-RNA CHIMERIC DUPLEXES
Overview
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.
About this Structure
Full crystallographic information is available from OCA.
Reference
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:7681688 Page seeded by OCA on Fri May 2 13:33:30 2008
