Related Experiment Video
Updated: Aug 12, 2026

Analyzing and Building Nucleic Acid Structures with 3DNA
Published on: April 26, 2013
Structural similarities between topoisomerases that cleave one or both DNA strands
1Whitehead Institute, 9 Cambridge Center, Cambridge, MA 02142, USA.
Abstract:
Type IA and type II DNA topoisomerases are distinguished by their ability to cleave one or two strands, respectively, of a DNA duplex. Both types have been proposed to use an "enzyme-bridging" mechanism, in which a break is formed in a DNA strand and a gap is opened between the broken pieces to allow passage of a second DNA strand or duplex segment. Although the type IA and type II topoisomerase structures appear overall quite different from one another, unexpected similarities between several structural elements suggest that members of the two subfamilies may use comparable mechanisms to bind and cleave DNA.
Related Concept Videos
DNA Helicases
DNA Topoisomerases
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
Homologous Recombination
Conservative Site-specific Recombination and Phase Variation
The recognition sites for Cre recombinase called LoxP...
Single-Strand DNA Binding Proteins
Inhibitors of Bacterial DNA Synthesis

