A0A7U6KEU0 · A0A7U6KEU0_9FIRM

Function

function

Releases the supercoiling and torsional tension of DNA, which is 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.

Caution

Lacks conserved residue(s) required for the propagation of feature annotation.

Catalytic activity

  • ATP-independent breakage of single-stranded DNA, followed by passage and rejoining.
    EC:5.6.2.1 (UniProtKB | ENZYME | Rhea)

Cofactor

Mg2+ (UniProtKB | Rhea| CHEBI:18420 )

Features

Showing features for binding site, site, active site.

TypeIDPosition(s)Description
Binding site10Mg2+ (UniProtKB | ChEBI); catalytic
Site62Interaction with DNA
Binding site106Mg2+ (UniProtKB | ChEBI); catalytic
Site169Interaction with DNA
Site177Interaction with DNA
Active site315O-(5'-phospho-DNA)-tyrosine intermediate
Site317Interaction with DNA

GO annotations

AspectTerm
Molecular FunctionDNA binding
Molecular FunctionDNA topoisomerase type I (single strand cut, ATP-independent) activity
Molecular Functionmagnesium ion binding
Biological ProcessDNA topological change

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    DNA topoisomerase 3
  • EC number
  • Alternative names
    • DNA topoisomerase III

Gene names

    • Name
      topB
    • ORF names
      lbkm_1287

Organism names

Accessions

  • Primary accession
    A0A7U6KEU0

Proteomes

Family & Domains

Features

Showing features for domain, region.

TypeIDPosition(s)Description
Domain4-137Toprim
Region188-193Interaction with DNA

Sequence similarities

Belongs to the type IA topoisomerase family.

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    727
  • Mass (Da)
    82,315
  • Last updated
    2021-06-02 v1
  • Checksum
    57E4678EECBAD954
MSQKIVVLAEKPSVGRDIARVLNCKKKINGAIEGNEYIVTWGLGHLVTLCDPEKYEDRYKEWNLADLPMLPKHMKLEVMRQTGKQFSAVKAQLSRKDVKEVIIATDAGREGELVARWILEKAGCKLPMKRLWISSVTDKAIKDGFRNLKPASAYDNLYRAAISRAEADWLVGINATRALTCKYNASLSCGRVQTPTLAMIAKREEEIRNFKPVPFYGLKAKLRIDGSYVTMDWTDAKSHSNRTFEEEKINRISQSLSNEQAVVKKVAKSQKKTYSPALYDLTELQRDANNRFNFSAKETLNIMQRLYENHKVLTYPRTDSRYLTSDMVGTLKERIEACANGPYRKMAAPLMRANIQGKPSFVDNSKVGDHHAIIPTEQYVNLDNMTNEERKIYDLVVKRFLAVMYPPFEYEQTTVEAEIGGETFGVKGKIVKSLGWKELYEGNTEEDFTSLPEMKEGMSYTIDSLTVTNGKTNPPAYFTEATLLSAMENPVKYMESKDKEDIKVLGETGGLGTVATRADIIEKLFHSFLIEKRGKEIFVTSKAKQLLELVPTDLKKPELTADWEKKLSQMANGTLKRDAFMNEIRTYAVELIGEIKSADGKFRHDNMTNHKCPDCGKNLLLVKGKNSTMRVCQDRECGYRETISRTSNARCPKCHKRMEIIGKGDTQQFVCACGHKERLSAFKERRKKEGGGVSKKDVNRALKELKKENEAPVNNAFAAAFAKLNLK

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AP018794
EMBL· GenBank· DDBJ
BBF42603.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

Disclaimer

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