DNA topoisomerase

DNA topoisomerase
Identifiers
EC number 5.99.1.2
CAS number 80449-01-0
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum

DNA topoisomerase or Topoisomerase(EC 5.99.1.2, type I DNA topoisomerase, untwisting enzyme, relaxing enzyme, nicking-closing enzyme, swivelase, omega-protein, deoxyribonucleate topoisomerase) is an enzyme with systematic name DNA topoisomerase.[1] This enzyme catalyses the following chemical reaction

ATP-independent breakage of single-stranded DNA, followed by passage and rejoining

These enzymes bring about the conversion of one topological isomer of DNA into another. There are two types of DNA topoisomerase; I and II. Both of these are further classified into sub families IA, IB, IIA, and IIB. DNA topoisomerase facilitates a transesterification reaction. Through this reaction DNA topoisomerase is able to break and rejoin the phosphate backbone of DNA.[2]

Topoisomerase probably evolved to carry out conformational and topological changes during cell replication and transcription. Only mammalian DNA topoisomerase II can break up two intertwined DNA strands. The unique ability of DNA unlinking is necessary for segregation of daughter chromosomes.[3]

References

  1. ↑ Gellert M (1981). "DNA topoisomerases". Annual Review of Biochemistry. 50: 879–910. doi:10.1146/annurev.bi.50.070181.004311. PMID 6267993.
  2. ↑ Wang JC (June 2002). "Cellular roles of DNA topoisomerases: a molecular perspective". Nature Reviews. Molecular Cell Biology. 3 (6): 430–40. doi:10.1038/nrm831. PMID 12042765.
  3. ↑ Liu, L. (1989). DNA Topoisomerase Poisons As Antitumor Drugs. Annual Review of Biochemistry,58(1), 351-375. doi:10.1146/annurev.biochem.58.1.351

See also

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