Figure 1.

In vitro antioxidant activity of AtPER1. Protection of DNA against cleavage by free radical attack by an AtPER1 fusion protein. A, pUC19 plasmid incubated with 3.0 μm Fe³⁺ for 0.5 h; B through D, pUC19 plasmid incubated with 0.3 μm Fe³⁺ for 0.5, 1, and 4 h, respectively. Lane 1, Without protein; lane 2, 200 μg mL^–1 AtPER1; lane 3, 100 μg mL^–1 AtPER1; lane 4, 50 μg mL^–1 AtPER1; lane 5, 20 μg mL^–1 AtPER1; lane 6, 200 μg mL^–1 bovine serum albumin (BSA); and lane 7, untreated pUC19 plasmid DNA. The major pUC19 band in lane 7 is the supercoiled plasmid that upon nicking by radical attack first will convert to a slower-moving open circular plasmid and will later be degraded to a DNA smear.