Single-molecule characterization of topoisomerase I and mutations using magnetic tweezers

Abstract

Processes such as protein transcription and replication produce torsional strain on DNA, resulting in supercoiling. A group of enzymes called topoisomerases (topo) are responsible for resolving these supercoils and maintaining the correct DNA topology in the cell. The type IA class of topoisomerases, cleave a strand of duplex DNA and pass a second strand through the break to relieve the torsional strain on DNA. The prototypical type IA topoisomerase, topo I of E. coli have been well characterized.