title: Effect of selective substitution of 5-bromocytosine on conformation of DNA triple helices.
abstract: Three triplex DNAs containing 5-bromocytosine[BrC] were studied by vibrational spectroscopy and molecular modelling. Firstly, three oligodeoxypyrimidines of 5'-(TC)3-T4-(BrCT)3 [CBrC], 5'-(TBrC)3-T4-(CT)3 [BrCC] and 5'-(TBrC)3-T4-(BrCT)3 [BrCBrC] were synthesized and then reacted with an oligodeoxypurine of 5'-(AG)3 at pH=4.5 in phosphate buffer respectively to form three comparative hairpin triplex named CY,YC and YY. The results of FT-Raman and IR revealed that YY is almost in A-like form, CY and YC are combinations of A-like form and B-like form, but A-form dominates in CY while B-form is equivalent as A-form in YC. The result is consistent with the theoretical analysis.
authors.affiliation: Institute of Chemistry, Chinese Academy of Sciences, Beijing.
authors.forename: M
authors.initials: M
authors.lastname: Liu
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.forename: W
authors.initials: W
authors.lastname: Deng
authors.forename: M
authors.initials: M
authors.lastname: Su
authors.forename: C
authors.initials: C
authors.lastname: Wang
authors.forename: S B
authors.initials: SB
authors.lastname: Lin
authors.forename: L S
authors.initials: LS
authors.lastname: Kan
authors.forename: C
authors.initials: C
authors.lastname: Bai
mesh_terms: D003596:Cytosine / Q000031:analogs & derivatives* / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D009838:Oligodeoxyribonucleotides; C103182:5-bromocytosine; D003596:Cytosine; D004247:DNA