title: [Unpaired bases in the B--Z junction of the supercoiled plasmid].
abstract: The restriction analysis has been used to establish that O-beta-diethylaminoethylhydroxylamine (OHA) produces modification of unpaired cytidines in the polylinker region adjacent to the Z-insert (dG-dC)10. (dG-dC)10 in the negatively supercoiled plasmid pGC20. The length of the transition region between B- and Z-portions of DNA is not less than 36 bps. The reaction of OHA with the unpaired cytidines in the B-Z junction is a fixing one and produces no secondary despiralling of the neighboring regions. The reaction with DNA proceeds much slower than the one with monomers and single-strand polynucleotides. The structural nonuniformity has been observed, which is manifested in the alternating B and "non-B" form DNA in the B-Z junction. It is suggested that these junctions may contain nucleotide sequences which are stable to violation of the B structure during the change in superhelical density of DNA.
authors.forename: B P
authors.initials: BP
authors.lastname: Ulanov
authors.forename: P P
authors.initials: PP
authors.lastname: Pozdeev
authors.forename: T I
authors.initials: TI
authors.lastname: Matorina
authors.forename: V V
authors.initials: VV
authors.lastname: Vasil'ev
authors.forename: A A
authors.initials: AA
authors.lastname: Vecher
mesh_terms: D001483:Base Sequence; D004262:DNA Restriction Enzymes; D004269:DNA, Bacterial / Q000235:genetics; D004278:DNA, Superhelical / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids; D015183:Restriction Mapping
chemical_list: D004269:DNA, Bacterial; D004278:DNA, Superhelical; D004262:DNA Restriction Enzymes
vernacular_title: Nesparennye osnovaniia v B--Z perekhodnoĭ oblasti superspiral'noĭ plazmidy.