Fig. 1

Characterization of G4-specific affinity of BioTASQ. a Structure of BioTASQ displaying a biotin affinity tag (red circles), and schematic representation of its open (left) and closed, quadruplex-associated conformation (right), in which the intramolecular G-quartet is formed. Schematic representation of a guanine-rich RNA sequence (guanines as gray squares) in its unfolded, random-coil and folded G4 structure. b Fluorescence analysis of pull-down experiments carried out with (1) FAM-labeled oligonucleotides (1 µM): either G4-DNA (F-MYC, F-SRC, and F-22AG), duplex-DNA (F-duplex) or G4-RNA (F-TERRA, F-TRF2, and F-RAS); (2) BioTASQ (20 µM); and (3) streptavidin-coated magnetic beads. c Competitive pull-down experiments performed with F-SRC and F-NRAS (1 µM), BioTASQ (20 µM) in the absence or presence of duplex-DNA competitors (ds17 or ds26, 20 µM) or DNA extracts (calf thymus DNA, ctDNA, 100 µM), or of molecular competitors (biotin (or Biot.), 80 µM or ^PNADOTASQ (or TASQ), 10 µM). All experiments were done in triplicates. Error bars represent SD