FIG. 1.

Structural organization of the 6,179-bp floR locus of plasmid R55. Regions which exhibit homology to the floR-carrying E. coli BN10660 plasmid (GenBank accession no. AF231986), to the pp-flo-carrying P. damselae plasmid pSP92088 (GenBank accession no. D37826), and to the S. enterica serovar Typhimurium DT104 antibiotic resistance gene cluster (GenBank accession no. AF071555) are indicated. The numbers of the homologous segments refer to their positions within the sequence of the plasmid R55 floR locus. The extent and the direction of transcription of the floR, orf1, and orf2 reading frames are marked by arrows. The solid box upstream of floR (DR) indicates the 99-bp direct repeat. The BglI restriction sites are abbreviated as B. The distance scale below the map of the floR locus is given in basepairs.