rOrf4 interaction with DNA. (A) DNA binding of rOrf4. Plasmid DNA pGEX-6p-3 (0.2 μg) was incubated with different amounts of rOrf4 and subsequently loaded onto 1% agarose gel for electrophoresis. Lane 1, 14-kb DNA marker; lane 2, pGEX-6p-3; lanes 3 to 6, pGEX-6p-3 incubation with 5, 10, 30, and 45 μg rOrf4; lanes 7 to10, pGEX-6p-3 incubation with 5, 10, 30, and 45 μg BSA. (B) DNA protection assay of rOrf4. Plasmid DNA pGEX-6p-3 (0.2 μg) was added to 10 mM H2O2 in the presence of FeSO4 after incubation with or without proteins. Lane 1, 14-kb DNA marker; lane 2, pGEX-6p-3; lanes 3 to 7, pGEX-6p-3 + 1 to 5 μg rOrf4+FeSO4 + H2O2; lane 8, pGEX-6p-3 + FeSO4 + H2O2.