Fig. 5

A A PQ-tree of a heavy metal RND efflux pump, corresponding to the third top scoring result in Table 1. B An illustration of an RND efflux pump consisting of an outer-membrane protein (OMP), an inner membrane protein (IMP), and a periplasmic membrane fusion protein (MFP) that connects the other two proteins. In addition, a two-component regulatory system consisting of a sensor/histidine kinase (HK) and response regulator (RR) enhances the transcription of the efflux pump genes. C Representative gene sequences of the three different RND efflux pumps found in plasmids (additional gene insertions and deletions may be present among the various instances of these pumps.) (1) A Czc-like heavy metal efflux pump, (2) A Czc-like heavy metal efflux pump with a missing OMP gene, (3) A Cus-like heavy metal efflux pump, exemplifying an inserted gene (CusF), (4) An Acr-like multidrug efflux pump. Additional details can be found in the text. D The presence-absence map of the three types of efflux pumps found in the plasmids of different genomes. The rows correspond to the rows in C, the columns correspond to the genomes in which instances were found, organized according to their taxonomic classes. A black cell indicates that the corresponding efflux pump is present in the plasmids of the genome. The labels below the map indicate the classes \(\alpha ,\beta ,\gamma ,\delta\)-Proteobacteria and Acidobacteriia