Names & Taxonomy
- Uniprot ID:
- O95985
- Entry Name:
- TOP3B_HUMAN
- Status:
- reviewed
- Protein Names:
- DNA topoisomerase 3-beta-1 (EC 5.99.1.2) (DNA topoisomerase III beta-1)
- Gene Names:
- TOP3B TOP3B1
- Gene Names Primary:
- TOP3B
- Organism:
- Homo sapiens (Human)
Structure
- Length:
- 862
- Sequence:
- MKTVLMVAEKPSLAQSIAKILSRGSLSSHKGLNGACSVHEYTGTFAGQPVRFKMTSVCGHVMTLDFLGKYNKWDKVDPAELFSQAPTEKKEANPKLNMVKFLQVEGRGCDYIVLWLDCDKEGENICFEVLDAVLPVMNKAHGGEKTVFRARFSSITDTDICNAMACLGEPDHNEALSVDARQELDLRIGCAFTRFQTKYFQGKYGDLDSSLISFGPCQTPTLGFCVERHDKIQSFKPETYWVLQAKVNTDKDRSLLLDWDRVRVFDREIAQMFLNMTKLEKEAQVEATSRKEKAKQRPLALNTVEMLRVASSSLGMGPQHAMQTAERLYTQGYISYPRTETTHYPENFDLKGSLRQQANHPYWADTVKRLLAEGINRPRKGHDAGDHPPITPMKSATEAELGGDAWRLYEYITRHFIATVSHDCKYLQSTISFRIGPELFTCSGKTVLSPGFTEVMPWQSVPLEESLPTCQRGDAFPVGEVKMLEKQTNPPDYLTEAELITLMEKHGIGTDASIPVHINNICQRNYVTVESGRRLKPTNLGIVLVHGYYKIDAELVLPTIRSAVEKQLNLIAQGKADYRQVLGHTLDVFKRKFHYFVDSIAGMDELMEVSFSPLAATGKPLSRCGKCHRFMKYIQAKPSRLHCSHCDETYTLPQNGTIKLYKELRCPLDDFELVLWSSGSRGKSYPLCPYCYNHPPFRDMKKGMGCNECTHPSCQHSLSMLGIGQCVECESGVLVLDPTSGPKWKVACNKCNVVAHCFENAHRVRVSADTCSVCEAALLDVDFNKAKSPLPGDETQHMGCVFCDPVFQELVELKHAASCHPMHRGGPGRRQGRGRGRARRPPGKPNPRRPKDKMSALAAYFV
- Proteomes:
- UP000005640
Function
- Function:
- 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 than 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 (By similarity). Possesses negatively supercoiled DNA relaxing activity.
- Catalytic Activity:
- ATP-independent breakage of single-stranded DNA, followed by passage and rejoining.
- Active Site:
- ACT_SITE 336 336 O-(5'-phospho-DNA)-tyrosine intermediate.
- Gene Ontology Go:
- condensed chromosome
nucleus
DNA binding
DNA topoisomerase activity
DNA topoisomerase type I activity
poly(A) RNA binding
chromosome segregation
DNA topological change - Gene Ontology Biological Process:
- chromosome segregation
DNA topological change - Gene Ontology Molecular Function:
- DNA binding
DNA topoisomerase activity
DNA topoisomerase type I activity
poly(A) RNA binding - Gene Ontology Cellular Component:
- condensed chromosome
nucleus - Keywords:
- Alternative splicing
Complete proteome
DNA-binding
Isomerase
Polymorphism
Reference proteome
Topoisomerase - Interacts With:
- Q6UY14-3; Q9UJV3-2; Q9UL42; Q7Z698; Q9Y2D8; Q8WV44