4.8. DNA Binding Assay

An agarose gel-retardation assay was carried out to determine the binding of peptides with DNA as described previously [50]. Different concentrations of peptides were mixed with 100 ng of bacterial plasmid pBR322 in a binding buffer (10 mM Tris-HCl, 5% glucose, 50 mg/mL BSA, 1 mM EDTA, and 20 mM KCl). Then, the mixture of DNA and peptide was incubated at 37 °C for 1 h followed by 1% agarose gel electrophoresis in 0.5% TBE buffer. Bands were detected using a UV illuminator (Bio-Rad, Hercules, CA, USA).