Integrase IntN1 of Bacteroides mobilizable transposon NBU1 and similar proteins, C-terminal catalytic domain
IntN1 is a tyrosine recombinase for the integration and excision of Bacteroides mobilizable transposon NBU1 from the host chromosome. IntN1 does not require strict homology between the recombining sites seen with other tyrosine recombinases. This family belongs to the superfamily of DNA breaking-rejoining enzymes, which share the same fold in their catalytic domain and the overall reaction mechanism. The catalytic domain contains six conserved active site residues. Their overall reaction mechanism involves cleavage of a single strand of a DNA duplex by nucleophilic attack of a conserved tyrosine to give a 3' phosphotyrosyl protein-DNA adduct. In the second rejoining step, a terminal 5' hydroxyl attacks the covalent adduct to release the enzyme and generate duplex DNA.
Jiyao W et al.(2023). "The conserved domain database in 2023.",