1d80
CRYSTAL STRUCTURE OF AN OLIGONUCLEOTIDE DUPLEX CONTAINING G.G BASE-PAIRS: THE INFLUENCE OF MISPAIRING ON DNA BACKBONE CONFORMATION
OverviewOverview
The structure of the G.G mispaired dodecanucleotide d(CGCGAATTGGCG)2 has been solved by x-ray crystallography and refined to an R factor of 18.8% at 2.2 A resolution for 3513 reflections. The dodecamer crystallizes as a B-type DNA double helix. It contains two G(anti).G(syn) base pairs--i.e., G-4/G-16(anti).G-21/G-9(syn). The Hoogsteen base pairing involves atoms O-6 and N-7 of the guanine in the syn conformation with atoms N-1 and N-2 of the anti-paired purine. One G.G base pair has a bifurcated hydrogen bond between G-4(N-1)...G-21(N-7) and G-4(N-1)...G-21(O-6). There is little overall structural distortion of the double helix induced as a consequence of the mispairing. The helical width is significantly increased by comparison with the structure of the native duplex, and the minor groove width in the 5'-AATT region is decreased. The G.G base pairing induces high-BII phosphate conformations at residues G-9 and T-20 in addition to more normal BII conformations at G-10 and G-22. It is suggested that these backbone aberrations provide signals for the facile repairability of G.G mispairs in DNA.
About this StructureAbout this Structure
Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of an oligonucleotide duplex containing G.G base pairs: influence of mispairing on DNA backbone conformation., Skelly JV, Edwards KJ, Jenkins TC, Neidle S, Proc Natl Acad Sci U S A. 1993 Feb 1;90(3):804-8. PMID:8430089 Page seeded by OCA on Fri May 2 13:33:11 2008