Competition with GQ-binding ligands

A total of 1 μM ‘CatG4-ext’ was denatured for 3 min at 100°C and refolded in Q buffer for 30 min at 22°C. It was then made up to 5 μM hemin and rested for 10 min. Different concentrations (0–200 μM) of a given GQ-binding ligand was added, and the solution equilibrated further for 10 min. Following this, the solution was made up to 500 μM BT and 1 mM H₂O₂ to initiate the biotinylation reaction, which proceeded for 30 min at 22°C prior to quenching by the addition of catalase. The DNA was then recovered by ethanol precipitation and co-dissolved with StAv prior to running on native gels for analysis.