topoisomeraseDNA

Topoisomerase is a class of enzymes crucial for managing the topological state of DNA. These enzymes are essential for DNA replication, transcription, recombination, and repair. DNA is a double helix, and during cellular processes, this helix can become overwound or underwound, leading to torsional stress. Topoisomerases work by cleaving one or both strands of the DNA backbone, allowing the DNA to relax, and then rejoining the cleaved strands.

There are two main types of topoisomerases: Type I and Type II. Type I topoisomerases typically introduce transient breaks in a single DNA strand, allowing the DNA to rotate around the intact strand. This rotation relieves torsional stress. Type II topoisomerases, on the other hand, introduce transient double-strand breaks. They then pass another segment of DNA through this break before resealing it. This mechanism allows for more complex topological rearrangements.

Both types of topoisomerases play vital roles in maintaining genome stability. Inhibitors of topoisomerases are important chemotherapeutic agents, as they target actively dividing cancer cells by interfering with DNA replication and repair processes. By preventing the proper manipulation of DNA topology, these drugs can lead to DNA damage and cell death. Understanding the mechanisms of topoisomerases is fundamental to comprehending DNA metabolism and developing effective therapeutic strategies.