title: Intermolecular triplex formation distorts the DNA duplex in the regulatory region of human papillomavirus type-11.
abstract: A conformational distortion in the DNA duplex at the regulatory region of human papillomavirus type-11 next to an intermolecular triplex, formed with a synthetic oligonucleotide, was investigated with several chemical probes. The sequence targeted for triplex formation borders on the binding sites for the regulatory proteins encoded by the viral E2 open reading frame. Dimethyl sulfate, diethyl pyrocarbonate, and OsO4 all react to a greater extent with nucleotides in the duplex that are immediately adjacent to the triplex as compared to other bases throughout the duplex. This hypermodification was observed on both the polypurine and polypyrimidine strands of the duplex DNA. Similar hyperreactivity of bases flanking a triplex also was seen when the contiguous target polypurine tract was effectively extended by mutating interrupting pyrimidines in the human papillomavirus type-11 sequence to purines. We propose that this hyperreactivity is due to a structural distortion caused by the junction between the triplex and the duplex tracts.
authors.affiliation: Department of Biochemistry, School of Medicine, University of Alabama, Birmingham 35294.
authors.forename: D A
authors.initials: DA
authors.lastname: Hartman
authors.forename: S R
authors.initials: SR
authors.lastname: Kuo
authors.forename: T R
authors.initials: TR
authors.lastname: Broker
authors.forename: L T
authors.initials: LT
authors.lastname: Chow
authors.forename: R D
authors.initials: RD
authors.lastname: Wells
mesh_terms: D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009693:Nucleic Acid Hybridization; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000302:isolation & purification; D027383:Papillomaviridae / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D013463:Sulfuric Acid Esters
chemical_list: D004279:DNA, Viral; D009838:Oligodeoxyribonucleotides; D013463:Sulfuric Acid Esters; C007482:dimethyl sulfate