FIG 3.
Phyletic distribution of three classes of histidine kinases. Presences of class I, II, and III histidine kinases (shown in the blue, orange, and red outmost rings, respectively) on the taxonomic tree were revealed using the Aquerium tool (see Materials and Methods for details). Taxonomic ranks are shown in gray. Phyla that contain representatives with HKIIIs are highlighted in pink.