title: Intramolecular dG.dG.dC triplex detected in Escherichia coli cells.
abstract: The formation of an intramolecular dG.dG.dC triplex in Escherichia coli cells is demonstrated at single-base resolution. The intramolecular dG.dG.dC triplex structure was probed in situ for E. coli cells containing plasmid DNAs with varying lengths of poly(dG).poly(dC) tracts employing chloroacetaldehyde. This chemical probe reacts specifically with unpaired DNA bases. The triplex structure formed with the poly(dG).poly(dC) tracts of 35 and 44 base-pairs, but not with 25 base-pairs. The triplex was detected only one to two hours after the chloramphenicol treatment: the period at which the extracted plasmid DNA revealed the maximal superhelical density.
authors.affiliation: La Jolla Cancer Research Foundation, CA 92037.
authors.forename: Y
authors.initials: Y
authors.lastname: Kohwi
authors.forename: S R
authors.initials: SR
authors.lastname: Malkhosyan
authors.forename: T
authors.initials: T
authors.lastname: Kohwi-Shigematsu
mesh_terms: D001483:Base Sequence; D004269:DNA, Bacterial / Q000737:chemistry* / Q000648:ultrastructure; D004926:Escherichia coli / Q000235:genetics*; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids
chemical_list: D004269:DNA, Bacterial