title: A stabilizing and denaturing dual-effect for natural polyamines interacting with G-quadruplexes depending on concentration.
abstract: Both G-quadruplexes and natural polyamines are intimately associated with tumor growth and proliferation. The effect of the natural polyamines on telomeric and some oncogenic G-quadruplexes including bcl-2, c-kit, and c-myc G-quadruplexes has been studied by using absorption, fluorescence, CD, and NMR methods. The results exhibited an interesting dual-effect depending on polyamineś concentration. Polyamines promote and stabilize G-quadruplexes under a lower concentration (less than 1mM) but denature G-quadruplexes under a higher concentration (more than 1mM). Probably the electrostatic and hydrophobic effect of polyamines and the hydrogen-bonding interaction between guanines and polyamines were respectively responsible for the stabilizing and denaturing effect.
authors.affiliation: National Laboratory for Molecular Sciences, Center for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing, PR China.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Sun
authors.forename: Junfeng
authors.initials: J
authors.lastname: Xiang
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.forename: Guangzhi
authors.initials: G
authors.lastname: Xu
authors.forename: Yalin
authors.initials: Y
authors.lastname: Tang
mesh_terms: D002942:Circular Dichroism; D054856:G-Quadruplexes; D019254:Genes, bcl-2; D016259:Genes, myc; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D011073:Polyamines / Q000737:chemistry; D011188:Potassium / Q000737:chemistry / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics; D055672:Static Electricity; D016615:Telomere / Q000235:genetics
chemical_list: D011073:Polyamines; D019009:Proto-Oncogene Proteins c-kit; D011188:Potassium