title: Triplex staples: DNA double-strand cross-linking at internal and terminal sites using psoralen-containing triplex-forming oligonucleotides.
abstract: A method has been developed to attach 4'-(hydroxymethyl)-4,5',8-trimethylpsoralen to the 5 position of thymine bases during solid-phase oligonucleotide synthesis. UV irradiation of triplex-forming oligonucleotides (TFOs) containing internally attached psoralens produces photoadducts at TpA steps within target duplexes, thus relaxing the constraints on selection of psoralen target sequences. Photoreaction of TFOs containing two psoralens, located at the 5'- and 3'-ends, has been used to create double-strand cross-links (triplex staples) at both termini of the TFO. Such complexes have no free single-stranded ends. TFOs containing 4'-(hydroxymethyl)-4,5',8-trimethylpsoralen, 3-methyl-2-aminopyridine, and 5-(3-aminoprop-2-ynyl)deoxyuridine formed photoadducts with target duplexes under near-physiological conditions.
authors.affiliation: School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Broughton-Head
authors.forename: Guomei
authors.initials: G
authors.lastname: Peng
authors.forename: Vicki E C
authors.initials: VE
authors.lastname: Powers
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Ovens
authors.forename: Keith R
authors.initials: KR
authors.lastname: Fox
authors.forename: Tom
authors.initials: T
authors.lastname: Brown
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004587:Electrophoresis, Agar Gel; D005363:Ficusin / Q000737:chemistry*; D015394:Molecular Structure; D009690:Nucleic Acid Conformation / Q000528:radiation effects; D009691:Nucleic Acid Denaturation; D009841:Oligonucleotides / Q000737:chemistry*; D017319:Photosensitizing Agents / Q000737:chemistry*; D044366:Transition Temperature
chemical_list: D003432:Cross-Linking Reagents; D009841:Oligonucleotides; D017319:Photosensitizing Agents; D004247:DNA; D005363:Ficusin