P78032 · TOP1_MYCPN

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.

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 site9Mg2+ (UniProtKB | ChEBI); catalytic
Site33Interaction with DNA
Binding site102Mg2+ (UniProtKB | ChEBI); catalytic
Site160Interaction with DNA
Site164Interaction with DNA
Active site340O-(5'-phospho-DNA)-tyrosine intermediate
Site342Interaction with DNA
Site535Interaction with DNA

GO annotations

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

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    DNA topoisomerase 1
  • EC number
  • Alternative names
    • DNA topoisomerase I
    • Omega-protein
    • Relaxing enzyme
    • Swivelase
    • Untwisting enzyme

Gene names

    • Name
      topA
    • ORF names
      MP572
    • Ordered locus names
      MPN_261

Organism names

Accessions

  • Primary accession
    P78032

Proteomes

Subcellular Location

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00001451561-711DNA topoisomerase 1

Interaction

Subunit

Monomer.

Protein-protein interaction databases

Structure

Family & Domains

Features

Showing features for domain, region, zinc finger.

TypeIDPosition(s)Description
Domain3-134Toprim
Domain150-604Topo IA-type catalytic
Region183-188Interaction with DNA
Zinc finger624-652C4-type 1
Zinc finger673-702C4-type 2

Sequence similarities

Belongs to the type IA topoisomerase family.

Keywords

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    711
  • Mass (Da)
    81,965
  • Last updated
    1997-02-01 v1
  • Checksum
    16B863588B06582E
MSKNLVVIESPNKVKTLQKYLPNDFEIVSTIGHIREMVHKNFGFNEADYSPVWEDWTKSKKKFSSLSFKGNLKGKKLLSKYDIIKSIKEKASKATNIYLATDPDREGEAISWHVYDVLDEKDKSKCQRITFNEITKNAVLDALKNPREIDQSWVQSQFARQILDRMIGFRLSRLLNNYLSAKSAGRVQSVALRFLEEREQEIRSFVPRFWWTLDVLLNPKAEGVREACANRSIPIVLREINPALRAGLKFEEEKSVSGIDFLDEASAKKFGEQLKGVFEVYNIDETKHYSSSPNSAYTTASLQKDAINKLGWSSKKVTLIAQHLYEGVSINGEQTALISYPRTDSTRLSAQFQQSCKEYILNHYGEKYLSNRIVSAKGKKGEKIIQDAHEAIHPTDINITPEMVKNAIKKDEFLLYRLIWIRTVASLMADCKKSHTHIRFINDGNKFYASSKSLVFDGYRKIYEHFENKESNDLYIDLDKIRVGDRFMAKDIKITARQTHPAARYTQASLIEALEKSNIGRPSTYNTMASVNLDRGYASLNKHAFHVTQLGEQVNEELSKHFGKIINKEFTKNMEKSLDEIAENKKNYQEFLRDFWSNFKEEVKLAEGSIQRVKKEKEFVGRDCPSCASPLLYRYTKRGNEKFVGCSNFPNCKYNEFSQNKPNLTLEKLEELCPECNSQLVKRRTKFNPNKTFVGCSNFPRCRYIKKDNAS

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
U00089
EMBL· GenBank· DDBJ
AAB96220.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

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