DNA topoisomerase 1, TOPRIM domain (IPR034149)

Short name: TOPRIM_TopoI

Overlapping homologous superfamilies

Domain relationships

  • TOPRIM domain (IPR006171)
    • DNA topoisomerase 1, TOPRIM domain (IPR034149)


This topoisomerase-primase (TOPRIM) domain is found in members of the type IA family of DNA topoisomerases (Topo IA) similar to Escherichia coli DNA topoisomerase I. Type IA DNA topoisomerases remove (relax) negative supercoils in the DNA by cleaving one strand of the DNA duplex, covalently linking to the 5' phosphoryl end of the DNA break, and allowing the other strand of the duplex to pass through the gap [PMID: 11239459]. E. coli DNA topoisomerase I is primarily involved in the relaxation of negatively supercoiled DNA by the stand passage mechanism [PMID: 12221296].

The TOPRIM domain has two conserved motifs, one of which centres at a conserved glutamate and the other one at two conserved aspartates (DxD). For topoisomerases the conserved glutamate is believed to act as a general base in strand joining and, as a general acid in strand cleavage. The DXD motif may co-ordinate Mg2+, a cofactor required for full catalytic function [PMID: 9722641].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.