Recombination R-triplex: H-bonds contribution to stability as revealed with minor base substitutions for adenine.

ABSTRACT: Several cellular processes involve alignment of three nucleic acids strands, in which the third strand (DNA or RNA) is identical and in a parallel orientation to one of the DNA duplex strands. Earlier, using 2-aminopurine as a fluorescent reporter base, we demonstrated that a self-folding oligonucleotide forms a recombination-like structure consistent with the R-triplex. Here, we extended this approach, placing the reporter 2-aminopurine either in the 5'- or 3'-strand. We obtained direct evidence that the 3'-strand forms a stable duplex with the complementary central strand, while the 5'-strand participates in non-Watson-Crick interactions. Substituting 2,6-diaminopurine or 7-deazaadenine for adenine, we tested and confirmed the proposed hydrogen bonding scheme of the A*(T.A) R-type triple

SUBMITTER: Shchyolkina AK 

PROVIDER: S-EPMC1500870 | biostudies-literature | 2006

REPOSITORIES: biostudies-literature