InnateDB: Systems Biology of the Innate Immune Response

Homo sapiens Protein: TOP3B

Summary

InnateDB Protein

IDBP-232169.6

Last Modified

2014-10-13 [Report errors or provide feedback]

Gene Symbol

TOP3B

Protein Name

topoisomerase (DNA) III beta

Synonyms

TOP3B1;

Species

Homo sapiens

Ensembl Protein

ENSP00000381773

InnateDB Gene

IDBG-2166 (TOP3B)

Protein Structure

UniProt Annotation

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. {ECO:0000250}.

Subcellular Localization

Disease Associations

Tissue Specificity

Isoform 1 is found in testis, heart and skeletal muscle. A 4 kb transcript which probably represents isoform 2 is found in thymus, kidney and pancreas. {ECO:0000269PubMed:9927731}.

Comments

Interactions

Number of Interactions

This gene and/or its encoded proteins are associated with 17 experimentally validated interaction(s) in this database.

Experimentally validated
Total	17 [view]
Protein-Protein	16 [view]
Protein-DNA	1 [view]
Protein-RNA	0
DNA-DNA	0
RNA-RNA	0
DNA-RNA	0

Gene Ontology

Molecular Function

Accession	GO Term
GO:0003677	DNA binding
GO:0003916	DNA topoisomerase activity
GO:0003917	DNA topoisomerase type I activity
GO:0044822	poly(A) RNA binding

Biological Process

GO:0006265	DNA topological change
GO:0007059	chromosome segregation

Cellular Component

GO:0000793	condensed chromosome
GO:0005634	nucleus

Protein Structure and Domains

PDB ID

InterPro

IPR000380 DNA topoisomerase, type IA
IPR003601 DNA topoisomerase, type IA, domain 2
IPR003602 DNA topoisomerase, type IA, DNA-binding domain
IPR006171 Toprim domain
IPR013497 DNA topoisomerase, type IA, central
IPR023405 DNA topoisomerase, type IA, core domain

PFAM

PF01751
PF13662
PF01131

PRINTS

PR00417

PIRSF

SMART

SM00436
SM00437
SM00493

TIGRFAMs

Post-translational Modifications

Modification

Cross-References

SwissProt