title: Stable recognition of TA interruptions by triplex forming oligonucleotides containing a novel nucleoside.
abstract: We have prepared the 2'-aminoethoxy derivative of the S nucleoside ((2AE)S) and incorporated it into triplex-forming oligonucleotides for recognition of TA interruptions within a target oligopurine tract. Fluorescence melting, UV melting, and DNase I footprinting experiments show that (2AE)S has greater affinity than G or S for a single TA interruption. Stable triplexes are formed at pH 6.0 at an 18-mer target site containing two TA interruptions, even though this contains eight C(+).GC triplets. Although (2AE)S and S produce stable triplexes at TA interruptions, they also interact with other base pairs, in particular, CG, although the selectivity for TA improves with increased pH.( 2AE)S is the best nucleoside described so far for recognition of TA within a triple-helix target.
authors.affiliation: School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.forename: David A
authors.initials: DA
authors.lastname: Rusling
authors.forename: Vicki E C
authors.initials: VE
authors.lastname: Powers
authors.forename: Oliver
authors.initials: O
authors.lastname: Lack
authors.forename: Sadie D
authors.initials: SD
authors.lastname: Osborne
authors.forename: Keith R
authors.initials: KR
authors.lastname: Fox
authors.forename: Tom
authors.initials: T
authors.lastname: Brown
mesh_terms: D001483:Base Sequence; D018983:DNA Footprinting; D003850:Deoxyribonuclease I; D003854:Deoxyribonucleotides / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013873:Thionucleotides / Q000737:chemistry
chemical_list: D003854:Deoxyribonucleotides; D009838:Oligodeoxyribonucleotides; D013873:Thionucleotides; D003850:Deoxyribonuclease I