title: Circular dichroism spectra demonstrate formation of the thrombin-binding DNA aptamer G-quadruplex under stabilizing-cation-deficient conditions.
abstract: It is noteworthy that the formation of the DNA G-quadruplex is induced by factors other than stabilizing cations because this event probably occurs in living cells. Previous studies have shown that thrombin-binding DNA aptamer (TBA) forms a chair-type intramolecular G-quadruplex structure that binds with thrombin protein in the absence of stabilizing cations. Here, we used circular dichroism (CD) spectroscopy to confirm G-quadruplex formation in the presence of thrombin without stabilizing cations. We obtained characteristic CD spectra that demonstrated that TBA forms the distinctive G-quadruplex structure. Additionally, we investigated G-quadruplex formation induced by change of solvent environment: the influence of low-temperature conditions and molecular crowding.
authors.affiliation: Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8562, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Nagatoishi
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Kouhei
authors.initials: K
authors.lastname: Tsumoto
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001665:Binding Sites; D002412:Cations; D002942:Circular Dichroism; D006147:Guanine / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D011485:Protein Binding; D013917:Thrombin / Q000737:chemistry*
chemical_list: D052157:Aptamers, Nucleotide; D002412:Cations; D046911:Macromolecular Substances; D006147:Guanine; D013917:Thrombin