FIGURE 3.

Phylogenetic tree of MerA protein homologs (plasmid MerA not included). Archaeal and bacterial clades are denoted with blue and red color, respectively, while purple-colored clades denote mixed lineages. Colors covering labels of lineages denote the three primary groups of MerA: Group A (light blue), Group B (light orange) and Group C (light green). The outer boxes right to the labels show the presence of MerB (light red box) and MerB-like (gray boxes) homologs in the genomes from which the MerA homologs were derived. Numbers in the light red and gray boxes denote how many of the MerA-encoding genomes within each collapsed node also encoded MerB or MerB-like homologs, respectively. The outgroup consists of 6 bacterial and archaeal dihydrolipoamide dehydrogenase sequences. Tree scale is in amino acid substitutions per site. Yellow stars denote lineages with representatives which their MerA activity has been confirmed. Single lineages not grouped with other clades are depicted with their gene ID and phylum assignment.