The integrase (Int) protein of coliphage HK022 can catalyze in Escherichia coli as well as in in vitro integrative and excisive recombinase-mediated cassette exchange reactions between plasmids as substrates. Atomic force microscopy images have revealed that in the protein-DNA complexes that are formed, the plasmid substrates are connected via one and not two pairs of attachment sites. This observation, together with the elucidation of intermediate co-integrates between the two circular plasmids, suggest that a sequential mechanism of the RMCE reaction is possible.
- Atomic force microscopy
- Bacteriophage HK022
- Recombinase-mediated cassette exchange
- Site-specific recombination