Unrooted phylogenetic tree (radial view) of the TrpEb protein family consisting of subfamily TrpEb_1 (top) and TrpEb_2 (bottom). Phylogenetic reconstruction of the inferred amino-acid sequence was accomplished by the neighbor-joining method using the PHYLIP program. Organismal acronyms are defined in Table 1. For economy of space, a single branch is used to represent proteins that have diverged very recently, for example, TrpEb_1 proteins from E. coli and S. typhimurium (Eco/Sty). Archaeal proteins are highlighted in magenta. The detailed order of branching for TrpEb_1 proteins in cyanobacteria and higher plants is shown in Figure 3. Probable pseudogenes are shown in yellow.