title: [Conformational transition of parallel DNA in solutions with decreased water activity].
abstract: Conformations of parallel deoxyoligonucleotides 5'd(CTATAGGGAT)3'/5'd(GATATCCCTA)3' and 5'd(TGATTGATCGATTGTTTGCATGCACACGTTTTTGTGAGCG)3'/'5'd (ACTAACTAGCTAACAAACGTACGTGTGCAAAAACACTCGC)3' were studied in solution by CD method. A cooperative change in the CD spectra is observed in trifluoroethanol (TFE) solutions at decreased water activity (relative humidity). This distinctive change is supposed to stem from a cooperative conformational transition of parallel double helix from a B-like form with C2'endo sugar conformation to a A-like form designated as Ap. The free energy difference between Ap- and B-like conformations of the parallel decaduplex is close to that for antiparallel decaduplex with the nucleotide sequence studied. A-phility of a parallel helix is dependent on its sequence.
authors: A K
authors: AK
authors: Shchelkina
authors: O F
authors: OF
authors: Borisova
authors: N A
authors: NA
authors: Churikov
authors: B K
authors: BK
authors: Chernov
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D008969:Molecular Sequence Data; D009691:Nucleic Acid Denaturation; D012996:Solutions; D014867:Water / Q000737:chemistry*
chemical_list: D012996:Solutions; D014867:Water; D004247:DNA
vernacular_title: Konformatsionnyĭ perekhod parallel'noĭ DNK v rastvorakh s ponizhennoĭ aktivnost'iu vody.