Properties of triple helices formed by parallel-stranded hairpins containing 8-aminopurines.

TitleProperties of triple helices formed by parallel-stranded hairpins containing 8-aminopurines.
Publication TypeJournal Article
Year of Publication2002
AuthorsAviñó, Anna, Frieden Miriam, Morales Juan Carlos, de la Torre Beatriz García, García Ramón Güimil, Azorín Ferran, Gelpí Josep-Lluis, Orozco Modesto, González Carlos, and Eritja Ramon
JournalNucleic Acids Res
Date Published2002 Jun 15
KeywordsAmines, Base Sequence, Biomolecular, Circular Dichroism, DNA, Electrophoretic Mobility Shift Assay, Guanine, Hot Temperature, Models, Molecular, Nuclear Magnetic Resonance, Nucleic Acid Conformation, Nucleic Acid Denaturation, Oligonucleotides, Purines, Pyrimidines, Salts

Parallel-stranded hairpins with a polypyrimidine sequence linked to a complementary purine carrying 8-aminopurines such as 8-aminoadenine, 8-aminoguanine and 8-aminohypoxanthine bind polypyrimidine sequences complementary (in an antiparallel sense) to the purine part by a triple helix. The relative stabilities of triplexes were assessed by UV-absorption melting experiments as a function of pH and salt concentration. Hairpins carrying 8-aminopurines give very stable triple helical structures even at neutral pH, as confirmed by gel-shift experiments, circular dichroism and nuclear magnetic resonance spectroscopy. The modified hairpins may be redesigned to cope with small interruptions in the polypyrimidine target sequence.