title: Evidence for the tetraplex structure of the d(GT)n repetitive sequences in solution.
abstract: The ability of oligonucleotides 3'-d(GT)5pO(CH2)6Opd(GT)5-5' (anti[d(GT)]) and 3'-d(GT)5pO(CH2)6Opd(GT)5-3' (par[par[d(GT)]) to form tertiary structures has been studied. Circular dichroism (CD) as well as the fluorescence of the ethidium bromide (EtBr) complexes with oligonucleotides and hydrodynamic volume measurements in solutions containing 0.01 M phosphate buffer, pH 7 and NaCl in concentrations from 0.1 M to 1 M, have been used. The data obtained in the temperature interval from 3 degrees C to 10 degrees C are in good agreement with the structure suggested earlier where the par[d(GT)] and anti[d(GT)] form structures with four parallel strands in which layers of four G-residues alternate with unpaired bulged-out T-residues. Ethidium bromide interacts with the structure in a cooperative manner. Two ethidium bromide molecules intercalate between two layers of four G-residues.
authors.affiliation: V.A. Engelhardt Institute of Molecular Biology, Russia Academy of Sciences, Moscow.
authors.forename: O F
authors.initials: OF
authors.lastname: Borisova
authors.forename: A K
authors.initials: AK
authors.lastname: Shchyolkina
authors.forename: E N
authors.initials: EN
authors.lastname: Timofeev
authors.forename: V L
authors.initials: VL
authors.lastname: Florentiev
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D012091:Repetitive Sequences, Nucleic Acid; D012996:Solutions
chemical_list: D009838:Oligodeoxyribonucleotides; D012996:Solutions