Names & Taxonomy

Uniprot ID:
Q969P6
Entry Name:
TOP1M_HUMAN
Status:
reviewed
Protein Names:
DNA topoisomerase I, mitochondrial (TOP1mt) (EC 5.99.1.2)
Gene Names:
TOP1MT
Gene Names Primary:
TOP1MT
Organism:
Homo sapiens (Human)

Structure

Length:
601
Sequence:
MRVVRLLRLRAALTLLGEVPRRPASRGVPGSRRTQKGSGARWEKEKHEDGVKWRQLEHKGPYFAPPYEPLPDGVRFFYEGRPVRLSVAAEEVATFYGRMLDHEYTTKEVFRKNFFNDWRKEMAVEEREVIKSLDKCDFTEIHRYFVDKAAARKVLSREEKQKLKEEAEKLQQEFGYCILDGHQEKIGNFKIEPPGLFRGRGDHPKMGMLKRRITPEDVVINCSRDSKIPEPPAGHQWKEVRSDNTVTWLAAWTESVQNSIKYIMLNPCSKLKGETAWQKFETARRLRGFVDEIRSQYRADWKSREMKTRQRAVALYFIDKLALRAGNEKEDGEAADTVGCCSLRVEHVQLHPEADGCQHVVEFDFLGKDCIRYYNRVPVEKPVYKNLQLFMENKDPRDDLFDRLTTTSLNKHLQELMDGLTAKVFRTYNASITLQEQLRALTRAEDSIAAKILSYNRANRVVAILCNHQRATPSTFEKSMQNLQTKIQAKKEQVAEARAELRRARAEHKAQGDGKSRSVLEKKRRLLEKLQEQLAQLSVQATDKEENKQVALGTSKLNYLDPRISIAWCKRFRVPVEKIYSKTQRERFAWALAMAGEDFEF
Proteomes:
UP000005640

Subcellular location

Subcellular Location:
Mitochondrion

Function

Function:
Releases the supercoiling and torsional tension of DNA introduced during duplication of mitochondrial DNA 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-(3'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 5'-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 5'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone (By similarity).
Catalytic Activity:
ATP-independent breakage of single-stranded DNA, followed by passage and rejoining.
Cofactor:
COFACTOR: Name=Ca(2+); Xref=ChEBI:CHEBI:29108;
Active Site:
ACT_SITE 559 559 O-(3'-phospho-DNA)-tyrosine intermediate.
Cross Reference Drug Bank:
DB00762 DB01030
Gene Ontology Go:
chromosome
mitochondrial nucleoid
mitochondrion
nucleus
DNA binding
DNA topoisomerase type I activity
DNA topoisomerase type II (ATP-hydrolyzing) activity
DNA replication
DNA topological change
Gene Ontology Biological Process:
DNA replication
DNA topological change
Gene Ontology Molecular Function:
DNA binding
DNA topoisomerase type I activity
DNA topoisomerase type II (ATP-hydrolyzing) activity
Gene Ontology Cellular Component:
chromosome
mitochondrial nucleoid
mitochondrion
nucleus
Keywords:
Alternative splicing
Complete proteome
DNA-binding
Isomerase
Mitochondrion
Polymorphism
Reference proteome
Topoisomerase
Transit peptide

Publication

PubMed ID:
11526219 14702039 16421571 15489334