title: Evaluation of effects of bivalent cations on the formation of purine-rich triple-helix DNA by ESI-FT-MS.
abstract: The GGA triplet repeats are widely dispersed throughout eukaryotic genomes. (GGA)n or (GGT)n oligonucleotides can interact with double-stranded DNA containing (GGA:CCT)n to form triple-stranded DNA. The effects of 8 divalent metal ions (3 alkaline-earth metals and 5 transition metals) on formation of these purine-rich triple-helix DNA were investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-MS). In the absence of metal ions, no triplex but single-strand, duplex, and purine homodimer ions were observed in mass spectra. The triple-helix DNA complexes were observed only in the presence of certain divalent ions. The effects of different divalent cations on the formation of purine-rich triplexes were compared. Transition-metal ions, especially Co(2+) and Ni(2+), significantly boost the formation of triple-helix DNA, whereas alkaline-earth metal ions have no positive effects on triplex formation. In addition, Ba(2+) is notably beneficial to the formation of homodimer instead of triplex.
authors.affiliation: Changchun Center of Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China.
authors.forename: Cuihong
authors.initials: C
authors.lastname: Wan
authors.forename: Meng
authors.initials: M
authors.lastname: Cui
authors.forename: Fengrui
authors.initials: F
authors.lastname: Song
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Liu
authors.forename: Shuying
authors.initials: S
authors.lastname: Liu
mesh_terms: D002413:Cations, Divalent / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D005583:Fourier Analysis; D008670:Metals / Q000737:chemistry*; D008673:Metals, Alkaline Earth / Q000737:chemistry; D019216:Metals, Heavy / Q000737:chemistry; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry; D011687:Purines / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D028561:Transition Elements / Q000737:chemistry
chemical_list: D002413:Cations, Divalent; D008670:Metals; D008673:Metals, Alkaline Earth; D019216:Metals, Heavy; D009841:Oligonucleotides; D011687:Purines; D028561:Transition Elements; D004247:DNA