Figure 6
A hypothetical ancestral common route for lysine, leucine, and arginine. The ancestral metabolic pathway, constituted by a restricted, unspecific set of enzymes, able to synthesize leucine, lysine, ornithine, and LL-diaminopimelate. Coloured genes are related to the extant lysine, leucine, and arginine biosynthetic ones. Dashed circles indicate more than one metabolic step. Genes coloured in white have no homologs in the metabolic routes studied in this work.