C-terminal catalytic domain of integrases from bacterial phages and conjugate transposons
This family of tyrosine based site-specific integrases is has origins in bacterial phages and conjugate transposons. One member is the integrase from Bacillus subtilis conjugative transposon ICEBs1. ICEBs1 can be excised and transfered to various recipients in response to DNA damage or high concentrations of potential mating partners. The 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.
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