Homologous Superfamily

DNA topoisomerase I, N-terminal (IPR035447)

Short name: DNA_topo_I_N

Overlapping entries

Description

Type I topoisomerases are ATP-independent enzymes (except for reverse gyrase), and can be subdivided according to their structure and reaction mechanisms: type IA (Topo IA; bacterial and archaeal topoisomerase I, topoisomerase III and reverse gyrase) and type IB (Topo IB; eukaryotic topoisomerase I and topoisomerase V). These enzymes are primarily responsible for relaxing positively and/or negatively supercoiled DNA, except for reverse gyrase, which can introduce positive supercoils into DNA. This function is vital for the processes of replication, transcription, and recombination. Unlike Topo IA enzymes, Topo IB enzymes do not require a single-stranded region of DNA or metal ions for their function. The type IB family of DNA topoisomerases includes eukaryotic nuclear topoisomerase I, topoisomerases of poxviruses, and bacterial versions of Topo IB [PMID: 17293019]. They belong to the superfamily of DNA breaking-rejoining enzymes, which share the same fold in their C-terminal catalytic domain and the overall reaction mechanism with tyrosine recombinases [PMID: 21087076,PMID: 9488644]. The C-terminal catalytic domain in topoisomerases is linked to a divergent N-terminal domain that shows no sequence or structure similarity to the N-terminal domains of tyrosine recombinases [PMID: 20644584,PMID: 17722649].

This superfamily represents the N-terminal domain of topoisomerase I from bacteria and virus [PMID: 7994576].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
GENE3D
SUPERFAMILY