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'''CONFORMATION OF THE GUANINE.8-OXOADENINE BASE PAIRS IN THE CRYSTAL STRUCTURE OF D(CGCGAATT(O8A)GCG)''' | '''CONFORMATION OF THE GUANINE.8-OXOADENINE BASE PAIRS IN THE CRYSTAL STRUCTURE OF D(CGCGAATT(O8A)GCG)''' | ||
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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=1D75 OCA]. | |||
==Reference== | ==Reference== | ||
Conformation of guanine-8-oxoadenine base pairs in the crystal structure of d(CGCGAATT(O8A)GCG)., Leonard GA, Guy A, Brown T, Teoule R, Hunter WN, Biochemistry. 1992 Sep 15;31(36):8415-20. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/1390625 1390625] | Conformation of guanine-8-oxoadenine base pairs in the crystal structure of d(CGCGAATT(O8A)GCG)., Leonard GA, Guy A, Brown T, Teoule R, Hunter WN, Biochemistry. 1992 Sep 15;31(36):8415-20. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/1390625 1390625] | ||
[[Category: Brown, T.]] | [[Category: Brown, T.]] | ||
[[Category: Guy, A.]] | [[Category: Guy, A.]] | ||
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[[Category: Leonard, G A.]] | [[Category: Leonard, G A.]] | ||
[[Category: Teoule, R.]] | [[Category: Teoule, R.]] | ||
[[Category: | [[Category: B-dna]] | ||
[[Category: | [[Category: Double helix]] | ||
[[Category: | [[Category: Mismatched]] | ||
[[Category: | [[Category: Modified]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 13:31:19 2008'' | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | |||
Revision as of 13:31, 2 May 2008
CONFORMATION OF THE GUANINE.8-OXOADENINE BASE PAIRS IN THE CRYSTAL STRUCTURE OF D(CGCGAATT(O8A)GCG)
OverviewOverview
The structure of the synthetic deoxydodecamer d(CGCGAATT(O8A)GCG)2 (O8A = 8-oxoadenine) has been determined by single-crystal X-ray diffraction techniques. The oligonucleotide crystallizes in the orthorhombic space group P2(1)2(1)2(1) with cell dimensions of a = 25.48 A, b = 41.84 A, and c = 64.91 A. The refinement has converged with an R-factor of 0.151 for 1119 reflections in the resolution range 8.0-2.25 A. Sixty-seven solvent molecules were located during the course of the refinement. The B-DNA helix consists of ten Watson-Crick base pairs and two guanine-8-oxoadenine (G.O8A) base pairs. In order to achieve hydrogen-bonding complementarity between the two bases, an unusual G(anti).O8A-(syn) wobble conformation is adopted. It is proposed that the G.O8A mispairs are held together by a network of four interbase hydrogen bonds which are the result of the formation of two reverse three-center hydrogen-bonding systems. These involve one carbonyl oxygen lone pair interacting with two hydrogen atoms. In a departure from previous observations of the characteristics of purine-purine anti-syn base pairs, lambda 1 and lambda 2, the angles between the glycosidic bonds and the C1'-C1' vector, are symmetric. A reassessment of the other purine-purine mispairs suggests that similar three-center hydrogen bonds may occur and make a contribution to stabilizing other base pairings.
About this StructureAbout this Structure
Full crystallographic information is available from OCA.
ReferenceReference
Conformation of guanine-8-oxoadenine base pairs in the crystal structure of d(CGCGAATT(O8A)GCG)., Leonard GA, Guy A, Brown T, Teoule R, Hunter WN, Biochemistry. 1992 Sep 15;31(36):8415-20. PMID:1390625 Page seeded by OCA on Fri May 2 13:31:19 2008