Figure 4From: A census of membrane-bound and intracellular signal transduction proteins in bacteria: Bacterial IQ, extroverts and introvertsDistribution of the signal transduction proteins follows the power law. A. Distribution of histidine kinases. B. Distribution of the total number of all signal transduction proteins except for histidine kinases encoded in a given genome. The symbols for various phyla are as in Fig. 2b.Back to article page