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IPR004085 is a DNA topoisomerase VI, subunit A.
<p>This entry represents subunit A of topoisomerase VI, a type IIB topoisomerase found predominantly in archaea, but also in a few eukayotes, such as the plant Arabidopsis thaliana [[cite:PUB00020804]]. This enzyme assembles as a heterotetramer, consisting of two A subunits required for DNA cleavage and two B subunits required for ATP hydrolysis. The B subunit is structurally similar to the ATPase domain of type IIA topoisomerases, but the A subunit is distinct, and instead shares homology with the Spo11 protein that mediates double-strand DNA breaks during meiotic recombination in eukaryotes [[cite:PUB00007202]]. The core of subunit A is a dimer, with a deep groove in which the DNA molecule is thought to bind, with the monomers separating during DNA transport. Therefore, though related to type IIA topoisomerases, topoisomerase VI may have a distinctive mechanism of action.</p> <p>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 [[cite:PUB00005437]]. 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 [[cite:PUB00020794], [cite:PUB00016842]]. DNA topoisomerases are divided into two classes: type I enzymes ([ec:5.6.2.2]; topoisomerases I, III and V) break single-strand DNA, and type II enzymes ([ec:5.6.2.2]; topoisomerases II, IV and VI) break double-strand DNA [[cite:PUB00020793]].</p> <p>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 [[cite:PUB00020795]].</p>
This description is obtained from EB-eye REST.
GO predictions are based solely on the InterPro-to-GO mappings published by EMBL-EBI, which are in turn based on the mapping of predicted domains to the InterPro dataset. The InterPro-to-GO mapping was last updated on , while the GO metadata was last updated on .
| GO term | Namespace | Name | Definition | Relationships |
|---|---|---|---|---|
| Molecular function | DNA binding | Any molecular function by which a gene product interacts selectively and non-covalently with DNA (deoxyribonucleic acid). | ||
| Molecular function | DNA topoisomerase type II (ATP-hydrolyzing) activity | Catalysis of a DNA topological transformation by transiently cleaving a pair of complementary DNA strands to form a gate through which a second double-stranded DNA segment is passed, after which the severed strands in the first DNA segment are rejoined; product release is coupled to ATP binding and hydrolysis; changes the linking number in multiples of 2. | ||
| Cellular component | Chromosome | A structure composed of a very long molecule of DNA and associated proteins (e.g. histones) that carries hereditary information. | ||
| Biological process | DNA topological change | The process in which a transformation is induced in the topological structure of a double-stranded DNA helix, resulting in a change in linking number. |
| Transcript | Name | Description | Predicted domains | Domain count |
|---|---|---|---|---|
| – | 9 | |||
| – | PREDICTED: DNA topoisomerase 6 subunit A-like [Cicer arietinum] gi|502121820|ref|XP_004497452.1| | 15 | ||
| – | DNA topoisomerase 6 subunit A; TAIR: AT5G02820.1 Spo11/DNA topoisomerase VI, subunit A protein; Swiss-Prot: sp|Q9LZ03|TOP6A_ARATH DNA topoisomerase 6 subunit A; TrEMBL-Plants: tr|A0A068F783|A0A068F783_LOTJA DNA topoisomerase 6 subunit A; Found in the gene: LotjaGi5g1v0072800 | 17 | ||
| – | DNA topoisomerase 6 subunit A; TAIR: AT5G02820.1 Spo11/DNA topoisomerase VI, subunit A protein; Swiss-Prot: sp|A2XFC1|TOP6A_ORYSI DNA topoisomerase 6 subunit A3; TrEMBL-Plants: tr|I1H6P7|I1H6P7_BRADI DNA topoisomerase 6 subunit A; Found in the gene: LotjaGi6g1v0346800 | 16 |
A list of co-occurring predicted domains within the L. japonicus gene space:
| Predicted domain | Source | Observations | Saturation (%) |
|---|---|---|---|
| cd00223 | CDD | 1 | 25.00 |