UniProt functional annotation for P14294

UniProt code: P14294.

Organism:		Escherichia coli (strain K12).
Taxonomy:		Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales; Enterobacteriaceae; Escherichia.
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. TOP3 is a potent decatenase. {ECO:0000255|HAMAP- Rule:MF_00953, ECO:0000269|PubMed:2553698, ECO:0000269|PubMed:6326814}.
Catalytic activity:		Reaction=ATP-independent breakage of single-stranded DNA, followed by passage and rejoining.; EC=5.6.2.1; Evidence={ECO:0000255|HAMAP- Rule:MF_00953, ECO:0000269|PubMed:6326814};
Cofactor:		Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000255|HAMAP-Rule:MF_00953, ECO:0000269|PubMed:6326814}; Name=Mn(2+); Xref=ChEBI:CHEBI:29035; Evidence={ECO:0000255|HAMAP-Rule:MF_00953, ECO:0000269|PubMed:6326814}; Name=Ca(2+); Xref=ChEBI:CHEBI:29108; Evidence={ECO:0000255|HAMAP-Rule:MF_00953, ECO:0000269|PubMed:6326814}; Note=Binds two Mg(2+) ions per subunit. The magnesium ions form salt bridges with both the protein and the DNA. Can also accept other divalent metal cations, such as Mn(2+) or Ca(2+). {ECO:0000255|HAMAP- Rule:MF_00953, ECO:0000269|PubMed:6326814};
Similarity:		Belongs to the type IA topoisomerase family. {ECO:0000255|HAMAP-Rule:MF_00953}.

Annotations taken from UniProtKB at the EBI.