The mechanism of type IA topoisomerases.

Dekker, N H; Rybenkov, V V; Duguet, M; Crisona, N J; Cozzarelli, N R; Bensimon, D; Croquette, V · Proc Natl Acad Sci U S A · 2002

basic_science · Level V

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Abstract

The topology of cellular DNA is carefully controlled by enzymes called topoisomerases. By using single-molecule techniques, we monitored the activity of two type IA topoisomerases in real time under conditions in which single relaxation events were detected. The strict one-at-a-time removal of supercoils we observed establishes that these enzymes use an enzyme-bridged strand-passage mechanism that is well suited to their physiological roles and demonstrates a mechanistic unity with type II topoisomerases.

Medical subject headings