Genetic organisation of Tn AO22. (A) Organisation of the mer operon and tnp genes. Select restriction sites are shown (E: Eco RI; N: Nco I; P: Pst I). IR: inverted repeats. The solid line between the Pst I site and left IR indicates a 1.1 kb section of pSV520 included in the 6.7 kb Pst I-Nco I fragment of pVS520::TnAO22 cloned into pGEM-T Easy. (B) Comparison of the res sites: Tn501 from P. aeruginosa pVS1 (Z00027), Tn21 from S. flexneri R100 (NC_002134), Tn4378 from C. metallidurans CH34 pMOL28 (NC_006525) and Tn5051 from Pseudomonas sp. (Y17719). Dots indicate nucleotides identical to those of TnAO22; dashes indicate gaps introduced to optimise identity. (C) Comparison of the putative amino acid sequences of resolvase of TnAO22 with those of Tn501 (CAA77327), Tn4378 (ABF13038) and Tn21 from S. flexneri (NP_052901) and Tn5051 (CAC14696). Arrow head indicates the presumptive serine involved in recombination. The shaded region indicates the conserved helix-turn-helix motif of resolvases.