TOP3A Releases the supercoiling and torsional tension of DNA introduced during the DNA replication and transcription by transiently cleaving and rejoining one strand of the DNA duplex. Introduces a single-strand break via transesterification at a target site in duplex DNA. The scissile phosphodiester is attacked by the catalytic tyrosine of the enzyme, resulting in the formation of a DNA-(5'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 3'-OH DNA strand. The free DNA strand then undergoes passage around the unbroken strand thus removing DNA supercoils. Finally, in the religation step, the DNA 3'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone. As an essential component of the RMI complex it is involved in chromosome separation and the processing of homologous recombination intermediates to limit DNA crossover formation in cells. Has DNA decatenation activity. It is required for mtDNA decatenation and segregation after completion of replication, in a process that does not require BLM, RMI1 and RMI2. Belongs to the type IA topoisomerase family. High expression is found in testis, heart, skeletal muscle and pancreas. 3 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: EC 5.99.1.2; Isomerase
Chromosomal Location of Human Ortholog: 11|11 B2
Cellular Component:  chromosome; mitochondrion; nucleus; PML body
Molecular Function:  DNA binding; DNA topoisomerase activity; DNA topoisomerase type I activity; isomerase activity; metal ion binding; single-stranded DNA binding; zinc ion binding
Biological Process:  chromosome separation; DNA topological change; mitochondrial DNA metabolic process
Reference #:  O70157 (UniProtKB)
Alt. Names/Synonyms: DNA topoisomerase 3-alpha; DNA topoisomerase III alpha; MGC106383; OTTMUSP00000008165; Top IIIa; Top3; Top3a; topoisomerase (DNA) 3 alpha; topoisomerase (DNA) III alpha; topoisomerase 3 alpha
Gene Symbols: Top3a
Molecular weight: 112,358 Da
Basal Isoelectric point: 8.73  Predict pI for various phosphorylation states
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TOP3A

Protein Structure Not Found.


Cross-references to other databases:  STRING  |  Reactome  |  BioGPS  |  Pfam  |  ENZYME  |  Phospho.ELM  |  NetworKIN  |  UniProtKB  |  Entrez-Gene  |  Ensembl Gene