FIG. 2.

Representation of plasmids used in this study. The positions of the three invariant residues of the integrase family are indicated, along with restriction sites used to construct mutant proteins. Core sites are represented by black circles, and attCs are shown by white boxes. The numbered arrows represent the PCR primers used to detect excision events, pACYC184-5′ (1) and pACYC184-3′ (2). bla, gene encoding β-lactamase; cat, gene encoding chloramphenicol acetyltransferase; intIl, gene encoding the integron integrase (IntI1); malE, gene encoding the maltose binding protein (MBP); ori, origin of replication; P_tac, tac promoter; P_tet, tetracycline promoter. Only relevant restriction sites are indicated.