Fig 1.

Description of the plasmids pMT85:arcAB and pMT85:arcABC. These plasmids were constructed by inserting the arcA and arcB genes into the BamHI and NotI sites of the plasmid pMT85 (27), generating pMT85:arcAB, and by inserting the arcC gene into the PfiMI and BamHI sites of pMT85:arcAB, resulting in the plasmid pMT85:arcABC. For details, see Materials and Methods. The transposase (Tpn) is located outside the inverted repeats and will not be integrated into the genome of the M. pneumoniae transformants. The expression unit in front of arcA contains a HindIII site, which, together with the closest HindIII site on the genome, facilitates recloning of the genomic site of transposon integration.