Figure 2.

Gyrase removes positive supercoils more rapidly than it introduces negative supercoils into relaxed DNA. Top: Gyrase activity on positively supercoiled DNA. A time course is shown for the relaxation of positive supercoils followed by the introduction of negative supercoils. Positively supercoiled [(+)SC] and negatively supercoiled [(−)SC] standards are shown. Middle: Expanded time course for the relaxation of (+)SC DNA by gyrase. Bottom: Time course for the introduction of negative supercoils into relaxed DNA (Rel) by gyrase. Gel images are representative of at least three independent experiments.