Parallel and Antiparallel A*A-T Intramolecular Triple Helices

Parallel and antiparallel A*A-T intramolecular triple helices.

Intramolecular triple helices have been obtained by folding back twice oligonucleotides formed by decamers bound by non-nucleotide linkers: dA10-linker-dA10-linker-dT10 and dA10-linker-dT10-linker-dA10. We have thus prepared two triple helices with forced third strand orientation, respectively antiparallel (apA*A-T) and parallel (pA*A-T) with respect to the adenosine strand of the Watson-Crick ...

Analytical resolution of parallel and antiparallel oligonucleotide triple helices formation and melting processes by means of Multivariate Curve Resolution

Spectroscopic studies of chimeric DNA-RNA and RNA 29-base intramolecular triple helices.

Fourier transform infrared (FTIR), UV absorption and exchangeable proton NMR spectroscopies have been used to study the formation and stability of two intramolecular pH-dependent triple helices composed by a chimeric 29mer DNA-RNA (DNA double strand and RNA third strand) or by the analogous 29mer RNA. In both cases decrease of pH induces formation of a triple helical structure containing either...

Discovery of a significant, nontopological preference for antiparallel alignment of helices with parallel regions in sheets.

To help elucidate the role of secondary structure packing preferences in protein folding, here we present an analysis of the packing geometry observed between alpha-helices and between alpha-helices and beta-sheets in 1316 diverse, nonredundant protein structures. Finite-length vectors were fit to the alpha-carbon atoms in each of the helices and strands, and the packing angle between the vecto...

Antiparallel, intramolecular triplex DNA stimulates homologous recombination in human cells.

The DNA motif 5'-AAGGGAGAAXGGGTATAGGGYAAGAGGGAA-3' (named XY32) is an H-palindrome and has been shown to undergo a superhelix-induced, pH-dependent structural transition to H-form (pyrimidine purineo pyrimidine triplex) DNA when X = Y = A (AA32) or X = Y = G (GG32), but when X = A and Y = G (AG32) or X = G and Y = A (GA32), the transition is much more difficult [Mirkin, S. (1987) Nature (London...