FIG. 8.

rBCP protects supercoiled plasmid DNA from nicking by H₂O₂. (A) Supercoiled (SC) pUC19 DNA (100 ng) (lane 1) was treated with 6 mM H₂O₂ for 30 min, resulting in nicked (N) pUC19 (lane 2). Reactions were also done in the presence of 0.1 μM rBCP in its native (lane 3) or heat-denatured “hd” (lane 4) state. Control reactions (lanes 1 and 2) were used as comparators for densitometry. (B) Densitometric analysis of the gel lanes in panel A, where black bars represent the nicked form of pUC19 and white bars depict supercoiled DNA. The assay is a representative from three independent experiments.