CD of homopolymer DNA-RNA hybrid duplexes and triplexes containing A-T or A-U base pairs.
AUTOR(ES)
Steely, H T
RESUMO
CD spectra and difference-CD spectra of (a) two DNA X RNA hybrid duplexes (poly[r(A) X d(U)] and poly[r(A) X d(T)]) and (b) three hybrid triplexes (poly-[d(T) X r(A) X d(T)], poly[r(U) X d(A) X r(U)], and poly[r(T) X d(A) X r(T)]) were obtained and compared with CD spectra of six A X U- and A X T-containing duplex and triplex RNAs and DNAs. We found that the CD spectra of the homopolymer duplexes above 260 nm were correlated with the type of base pair present (A-U or A-T) and could be interpreted as the sum of the CD contributions of the single strands plus a contribution due to base pairing. The spectra of the duplexes below 235 nm were related to the polypurine strands present (poly-[r(A)] or poly[d(A)]). We interpret the CD intensity in the intermediate 255-235 nm region of these spectra to be mainly due to stacking of the constituent polypurine strands. Three of the five hybrids (poly[r(A) X d(U)], poly[r(A) X d(T)], and poly[d(T) X r(A) X d(T)]) were found to have heteronomous conformations, while poly[r(U) X d(A) X r(U)] was found to be the most A-like and poly[r(T) X d(A) X r(T)], the least A-like.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=341356Documentos Relacionados
- Vacuum UV CD spectra of homopolymer duplexes and triplexes containing A.T or A.U base pairs.
- DNA-RNA hybrid duplexes containing oligo(dA:rU) sequences are exceptionally unstable and may facilitate termination of transcription.
- A new model for DNA containing A.T and I.C base pairs.
- The structure of a DNA-RNA hybrid.
- Characterization of imperfect DNA duplexes containing unpaired bases and non-Watson-Crick base pairs.