FIGURE 6.

Conservation of GGPP synthases in the MTC and closely related mycobacteria. GGPP synthases appear to have assumed additional wider importance in mycobacteria, as evidenced by the retention of Rv3383c/idsB despite loss of the remaining isoTb operon. Retention of orthologs for both Rv3383c/idsB and Rv0562/grcC1, based on both sequence similarity and genome positioning, is found in all sequenced members of the Mycobacterium family derived from the last common ancestor of the MTC and M. marinum. Species designated by genus and species initials (i.e., Mt, M. tuberculosis; Mb, M. bovis; Ma, M. africanum; Mc, M. canettii; Mm, M. marinum; Mu, M. ulcerans; Ml, M. leprae; Ms, M. smegmatis) and genes as annotated in the Mtb genome (i.e., either grcC1 or idsB), with the next closest ids homolog from M. smegmatis shown as the outgroup sequence). Not that while many of the listed species do contain other IDS encoding genes, these are relatively distantly related to those shown here.