title: Identification of Compounds that Selectively Stabilize Specific G-Quadruplex Structures by Using a Thioflavin T-Displacement Assay as a Tool.
abstract: Small molecules are used in the G-quadruplex (G4) research field in vivo and in vitro, and there are increasing demands for ligands that selectively stabilize different G4 structures. Thioflavin T (ThT) emits an enhanced fluorescence signal when binding to G4 structures. Herein, we show that ThT can be competitively displaced by the binding of small molecules to G4 structures and develop a ThT-displacement high-throughput screening assay to find novel and selective G4-binding compounds. We screened approximately 28 000 compounds by using three different G4 structures and identified eight novel G4 binders. Analysis of the structural conformation and stability of the G4 structures in presence of these compounds demonstrated that the four compounds enhance the thermal stabilization of the structures without affecting their structural conformation. In addition, all four compounds also increased the G4-structure block of DNA synthesis by Taq DNA polymerase. Also, two of these compounds showed selectivity between certain Schizosaccharomyces pombe G4 structures, thus suggesting that these compounds or their analogues can be used as selective tools for G4 DNA studies.
authors.affiliation: Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, 901 87, Sweden.
authors.forename: Jan
authors.identifier: http://orcid.org/0000-0001-6871-7663
authors.initials: J
authors.lastname: Jamroskovic
authors.affiliation: Department of Chemistry, Umeå University, Umeå, 901 87, Sweden.
authors.forename: Madeleine
authors.identifier: http://orcid.org/0000-0002-5890-9271
authors.initials: M
authors.lastname: Livendahl
authors.affiliation: Laboratories for Chemical Biology Umeå, Chemical Biology Consortium Sweden, Department of Chemistry, Umeå University, Umeå, 901 87, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Eriksson
authors.affiliation: Department of Chemistry, Umeå University, Umeå, 901 87, Sweden.
authors.forename: Erik
authors.identifier: http://orcid.org/0000-0003-2523-1940
authors.initials: E
authors.lastname: Chorell
authors.affiliation: Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, 901 87, Sweden.
authors.forename: Nasim
authors.identifier: http://orcid.org/0000-0002-4541-7702
authors.initials: N
authors.lastname: Sabouri
mesh_terms: D052160:Benzothiazoles; D005453:Fluorescence; D054856:G-Quadruplexes; D057166:High-Throughput Screening Assays; D008024:Ligands; D013844:Thiazoles / Q000737:chemistry*
chemical_list: D052160:Benzothiazoles; D008024:Ligands; D013844:Thiazoles; C009462:thioflavin T
keywords: DNA structures; G-quadruplexes; dyes; high-throughput screening; nucleobases