ActS/PrrB/RegB family redox-sensitive histidine kinase
This redox-responsive histidine kinase, found in alpha-proteobacteria, shows strong sequence conservation, including the notable motif [VA]AAAAHELGTPxTI. It always acts as a partner to an ActR/PrrA/RegA family global response regulator transcription factor in a two-component sensory transduction system. Lineage-specific names and gene symbols given to this histidine kinase reflect downstream regulator changes such as entry into stationary phase, anaerobic expression of photosynthesis genes, and survival of exposure to low pH.