DNA transport by a type II topoisomerase: direct evidence for a two-gate mechanism.

作者：Joaquím Roca, James M. Berger, Stephen C. Harrison, James C. Wang · 发表于：Proceedings of the National Academy of Sciences · 年份：1996 · DOI：10.1073/pnas.93.9.4057 · 被引用次数：201 · 研究领域：Cancer therapeutics and mechanisms、DNA and Nucleic Acid Chemistry、DNA Repair Mechanisms

Recent biochemical and crystallographic results suggest that a type II DNA topoisomerase acts as an ATP-modulated clamp with two sets of jaws at opposite ends: a DNA-bound enzyme can admit a second DNA through one set of jaws; upon binding ATP, this DNA is passed through an enzyme-mediated opening in the first DNA and expelled from the enzyme through the other set of jaws. Experiments based on the introduction of reversible disulfide links across one dimer interface of yeast DNA topoisomerase II have confirmed this mechanism. The second DNA is found to enter the enzyme through the gate formed by the N-terminal parts of the enzyme and leave it through the gate close to the C termini.