ML tree of PK protein sequences. Phylogenetic tree constructed from ATP dependent pyruvate kinases (PK) based on 297 aligned aa positions. Color coding and labelling is as in Figures 1A and 2A, except bootstrap values below 50% are shown where indicative of LGT events between eubacteria and eukaryotes (the branching of Trichomonas and cyanobacteria). Note that the four amitochondriate protists do not branch together. The root of the tree was chosen arbitrarily for display purposes.