title: Structures of homopurine-homopyrimidine tract in superhelical DNA.
abstract: For homopurine-homopyrimidine tracts in superhelical DNA, we propose a structure involving Watson-Crick and Hoogsteen paired triple helixes, hairpin loops and unstructured domains. Topologically, the whole structure is equivalent to an open region. The proposed structure is consistent with available S1 cleavage, pH and alkylation data and energetics under superhelical stress; this new structure is a much more probable candidate than the one proposed by us recently (V.I. Lyamichev, S.M. Mirkin & M.D. Frank-Kamenetskii, J. Biomole. Str. Dyns 3, 327-338, 1985).
authors.affiliation: Institute of Molecular Genetics, USSR Academy of Sciences, Moscow.
authors.forename: V I
authors.initials: VI
authors.lastname: Lyamichev
authors.forename: S M
authors.initials: SM
authors.lastname: Mirkin
authors.forename: M D
authors.initials: MD
authors.lastname: Frank-Kamenetskii
mesh_terms: D001483:Base Sequence; D004278:DNA, Superhelical; D008956:Models, Chemical; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D011687:Purines; D011743:Pyrimidines
chemical_list: D004278:DNA, Superhelical; D011687:Purines; D011743:Pyrimidines