Binding between G Quadruplexes at the Homodimer Interface of the Corn RNA Aptamer Strongly Activates Thioflavin T Fluorescence.

ABSTRACT: Thioflavin T (ThT) is widely used for the detection of amyloids. Many unrelated DNAs and RNAs that contain G-quadruplex motifs also bind ThT and strongly activate its fluorescence. To elucidate the structural basis of ThT binding to G quadruplexes and its fluorescence turn-on, we determined its co-crystal structure with the homodimeric RNA Corn, which contains two G quadruplexes. We found that two ThT molecules bind in the dimer interface, constrained by a G quartet from each protomer into a maximally fluorescent planar conformation. The unliganded Corn homodimer crystal structure reveals a collapsed fluorophore-binding site. In solution, Corn must fluctuate between this and an open, binding-competent conformation. A co-crystal structure with another benzothiazole derivate, thiazole orange

SUBMITTER: Sjekloca L 

PROVIDER: S-EPMC6697623 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature