Fig. 2. ct643 encodes a functional topoisomerase I.
A. SDS PAGE gel electrophoresis of purified CT643 (TopA) stained with Coomassie brilliant blue. The size of protein markers (M) in kDa is indicated to the left.
B. CT643 relaxes supercoiled DNA. Supercoiled plasmid was incubated with increasing concentrations of CT643.