C-terminal catalytic domain of recombinase RitA, a component of the recombinase trio.
Recombinases RitA (also known as pAE1), RitB, and RitC are encoded by three adjacent and overlapping genes. Collectively they are known as the Recombinase in Trio (RIT). This RitA family includes various bacterial integrases and integrases from the deletion-prone region of plasmid pAE1 of Alcaligenes eutrophus H1. All three integrases contain a catalytic motif, suggesting that they are all active enzymes. However, their specific roles are not fully understood. All three families belong 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 is essentially identical and 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.",