S
IPR018522

DNA topoisomerase, type IIA, conserved site

InterPro entry
Short nameTopoIIA_CS

Description

DNA topoisomerases regulate the number of topological links between two DNA strands (i.e. change the number of superhelical turns) by catalysing transient single-or double-strand breaks, crossing the strands through one another, then resealing the breaks
[7]
. These enzymes have several functions: to remove DNA supercoils during transcription and DNA replication; for strand breakage during recombination; for chromosome condensation; and to disentangle intertwined DNA during mitosis
[3, 5]
. DNA topoisomerases are divided into two classes: type I enzymes (
5.6.2.2
; topoisomerases I, III and V) break single-strand DNA, and type II enzymes (
5.6.2.2
; topoisomerases II, IV and VI) break double-strand DNA
[4]
.

Type II topoisomerases are ATP-dependent enzymes, and can be subdivided according to their structure and reaction mechanisms: type IIA (topoisomerase II or gyrase, and topoisomerase IV) and type IIB (topoisomerase VI). These enzymes are responsible for relaxing supercoiled DNA as well as for introducing both negative and positive supercoils
[2]
.

DNA topoisomerase II (
5.99.1.3
)
[6, 1, 7]
is one of the two types of enzyme that catalyze the interconversion of topological DNA isomers. Type II topoisomerases are ATP-dependent and act by passing a DNA segment through a transient double-strand break. Topoisomerase II is found in phages, archaebacteria, prokaryotes, eukaryotes, and in African Swine Fever virus (ASF). Bacteriophage T4 topoisomerase II consists of three subunits (the product of genes 39, 52 and 60). In prokaryotes and in archaebacteria the enzyme, known as DNA gyrase, consists of two subunits (genes GyrA and GyrB). In some bacteria, a second type II topoisomerase has been identified; it is known as topoisomerase IV and is required for chromosome segregation, it also consists of two subunits (genes parC and parE). In eukaryotes, type II topoisomerase is a homodimer.

References

1.DNA topoisomerases. Sharma A, Mondragon A. Curr. Opin. Struct. Biol. 5, 39-47, (1995). View articlePMID: 7773745

2.Structure and function of type II DNA topoisomerases. Watt PM, Hickson ID. Biochem. J. 303 ( Pt 3), 681-95, (1994). View articlePMID: 7980433

3.Cellular roles of DNA topoisomerases: a molecular perspective. Wang JC. Nat. Rev. Mol. Cell Biol. 3, 430-40, (2002). View articlePMID: 12042765

4.Phylogenomics of type II DNA topoisomerases. Gadelle D, Filee J, Buhler C, Forterre P. Bioessays 25, 232-42, (2003). View articlePMID: 12596227

5.DNA topoisomerases: structure, function, and mechanism. Champoux JJ. Annu. Rev. Biochem. 70, 369-413, (2001). View articlePMID: 11395412

6.DNA topoisomerases. Sternglanz R. Curr. Opin. Cell Biol. 1, 533-5, (1989). View articlePMID: 2560656

7.The mechanisms of DNA topoisomerases. Roca J. Trends Biochem. Sci. 20, 156-60, (1995). View articlePMID: 7770916

GO terms

Cross References

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