Helix Destabilization Assay Protocol

The standard helix destabilizing assay was performed as previously described (Shu et al.2019 (link)). Briefly, the indicated recombinant protein and 0.1 pmol/L of HEX-labeled helix substrate were added to the standard reaction mix containing 50 mmol/L HEPES-KOH (pH 8.0), 50 mmol/L NaCl, 2 mmol/L MgCl₂, 5 mmol/L ATP and 20 U RNasin (Promega). After incubation at 37 °C, the reaction was terminated by adding 10 × loading buffer [100 mmol/L Tris-HCl, 1% SDS, 50% glycerol, and bromophenol blue (pH 7.5)]. The mixtures were then electrophoresed on 15% native-PAGE gels, followed by scanning with a Typhoon 9500 imager (GE Healthcare, Piscataway, NJ).