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Summary of topoisomerase types and catalytic mechanisms. The topoisomerases are categorized based on whether they catalyze single- (type I) or double-stranded (type II) DNA breaks. The type I topoisomerases are further subdivided to type IA, IB and IC.
Topoisomerase is an essential enzyme that aids in the DNA replication process, segregation of chromosomes, transcription, and also in recombination. It was first found by J.C. Wang in the 1970s while working on Escherichia coli. It was the type I topoisomerase.
DNA topoisomerases solve the topological problems associated with DNA replication, transcription, recombination, and chromatin remodeling by introducing temporary single- or double-strand breaks in the DNA. In addition, these enzymes fine-tune the steady-state level of DNA supercoiling both to facil ….
Topoisomerases, or DNA topoisomerases, are enzymes that create single or double-stranded nicks in DNA during its replication or transcription to relieve the stress in a supercoiled DNA molecule. Thus, topoisomerases change the topology of the DNA strand. The first DNA topoisomerase was discovered by James Wang in 1971.
Human topoisomerases comprise a family of six enzymes: two type IB (TOP1 and mitochondrial TOP1 (TOP1MT), two type IIA (TOP2A and TOP2B) and two type IA (TOP3A and TOP3B) topoisomerases.
This reports the discovery of the first DNA topoisomerase, and proposes the transesterification mechanism of DNA strand breakage and rejoining.
The type IIA topos include prokaryotic DNA gyrase (gyrase) and topoisomerase IV (topo IV), and eukaryotic topoisomerase II (topo II) (Figure 4A). The general mechanism for the type II topos begins with the binding of one DNA duplex, termed the gate segment (G-segment), at the DNA gate.
DNA topoisomerases solve the topological problems associated with DNA replication, transcription, recombination, and chromatin remodeling by introducing temporary single- or double-strand breaks in the DNA.
Topoisomerases introduce transient DNA breaks to relax supercoiled DNA, remove catenanes and enable chromosome segregation. Human cells encode six topoisomerases (TOP1, TOP1mt, TOP2α, TOP2β ...
DNA topoisomerases, capable of manipulating DNA topology, are ubiquitous and indispensable for cellular survival due to the numerous roles they play during DNA metabolism. As we review here, current structural approaches have revealed unprecedented insights into the complex DNA-topoisomerase interac ….