?
Integron integrase and similar protiens, C-terminal catalytic domain Integron integrases mediate site-specific DNA recombination between a proximal primary site (attI) and a secondary target site (attC) found within mobile gene cassettes encoding resistance or virulence factors. Unlike other site specific recombinases, the attC sites lack sequence conservation. Integron integrase exhibits broader DNA specificity by recognizing the non-conserved attC sites. The structure shows that DNA target site recognition are not dependent on canonical DNA but on the position of two flipped-out bases that interact in cis and in trans with the integrase. Integron-integrases are present in many natural occurring mobile elements, including transposons and conjugative plasmids. Vibrio, Shewanella, Xanthomonas, and Pseudomonas species harbor chromosomal super-integrons. All integron-integrases carry large inserts unlike the TnpF ermF-like proteins also seen in this group.
|