Schematic representation of F-type IV secretion systems (T4SSA) for conjugal DNA transfer of L. pneumophila. In green and orange, tra and trb genes respectively. L. long, Legionella longbeachae; P, Plasmid; C, Chromosome; ycaO, Protein of unknown function with a YcaO like-domain; tfu, Protein of unknown function with a TfuA domain; pil, Pilus assembly protein precursor; t, transposase; E. coli, Escherichia coli; R. beeli, Rickettsia beeli; pha, Phage repressor; int, integrase; pin, site-specific DNA recombinase e14 prophage; R; repeat. Yellow squares represent flanking repeats, with length and percentage of identity between repeats in parenthesis. tRNAs, position in the genome in parenthesis.