title: Adenine affects the structure and stability of telomeric sequences.
abstract: Adenine occurs in the strand containing repeated G clusters in the telomeric DNA of a variety of organisms, including that of humans. The role of adenine has been investigated by constructing two sets of oligonucleotides each with one, two, or four copies of the telomeric sequence dTTTAGGG together with a control sequence in which T replaces the A residue, dTTTTGGG. Comparison of the stability and spectral properties of these two sequences in the presence of Na+ or K+ affords a basis for defining the role of adenine in these structures. In Na+, the A residue stabilizes the structure formed by each oligomer significantly, presumably by a base-pairing interaction with T. In K+, by contrast, there is little difference in stability. In two- and four-copy oligomers, the A sequence has a different structure from its T analog, as detected by CD spectroscopy. In the presence of either Na+ or K+, the tetraplexes of A and T interact with intercalators.
authors.affiliation: Department of Chemistry, New York University, New York 10003.
authors.forename: Q
authors.initials: Q
authors.lastname: Guo
authors.forename: M
authors.initials: M
authors.lastname: Lu
authors.forename: N R
authors.initials: NR
authors.lastname: Kallenbach
mesh_terms: D000225:Adenine; D001483:Base Sequence; D002942:Circular Dichroism; D003432:Cross-Linking Reagents; D004247:DNA / Q000737:chemistry*; D008745:Methylation; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry* / Q000528:radiation effects; D013329:Structure-Activity Relationship; D016615:Telomere / Q000502:physiology*; D013816:Thermodynamics; D013941:Thymine; D014466:Ultraviolet Rays
chemical_list: D003432:Cross-Linking Reagents; D009838:Oligodeoxyribonucleotides; D004247:DNA; D000225:Adenine; D013941:Thymine