title: Stabilization of unstable CGC+ triplex DNA by single-walled carbon nanotubes under physiological conditions.
abstract: Triplex formation is a promising strategy for realizing artificially controlling of gene expression, reversible assembly of nanomaterials and DNA nanomachine and single-walled nanotubes (SWNTs) have been widely used as gene and drug delivery vector or as 'building blocks' in nano-/microelectronic devices. CGC(+) triplex is not as stable as TAT triplex. The poor stability of CGC(+) triplex limits its use in vitro and in vivo. There is no ligand that has been reported to selectively stabilize CGC(+) triplets rather than TAT. Here, we report that SWNTs can cause d(CT) • d(AG) duplex disproportionation into triplex d(C(+)T) • d(AG) • d(CT) and single-strand d(AG) under physiological conditions. SWNTs can reduce the stringency of conditions for CGC(+) triplex formation studied by UV-vis, CD, DNA melting, light scattering and atomic force microscopy. Further studies indicate that electrostatic interaction is crucial for d(CT) • d(AG) repartition into triplex d(C(+)T) • d(AG) • d(CT). Our findings may facilitate utilization of SWNTs-DNA complex in artificially controlling of gene expression, nanomaterials assembly and biosensing.
authors.affiliation: Division of Biological Inorganic Chemistry, State Key Laboratory of Rare Earth Resource Utilization, Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Changchun, Jilin 130022, China.
authors.forename: Yujun
authors.initials: Y
authors.lastname: Song
authors.forename: Lingyan
authors.initials: L
authors.lastname: Feng
authors.forename: Jinsong
authors.initials: J
authors.lastname: Ren
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Qu
mesh_terms: D003596:Cytosine / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009691:Nucleic Acid Denaturation; D055672:Static Electricity
chemical_list: D037742:Nanotubes, Carbon; C051802:triplex DNA; D006147:Guanine; D003596:Cytosine; D004247:DNA