FIG 3.

Chemoreceptor repertoire of P. aeruginosa PAO1. Ligand-binding domains with parallel helix or α/β folds are shown in blue and orange, respectively. HAMP (histidine kinases, adenyl cyclases, methyl-accepting proteins, and phosphatases) and signaling domains are represented as green cylinders, whereas transmembrane regions and signaling domains are shown in blue. No HAMP domains were identified in Aer, BdlA, McpA, McpS, and PA4290. McpB/Aer2 is the only chemoreceptor that carries a C-terminal pentapeptide (in red) that acts as an additional CheR binding site (11). 4HB, four helix bundle; Cache, calcium channels and chemotaxis receptors; HBM, helical bimodular; PilJ, N-terminal domain of type IV pilus chemoreceptor; NIT, nitrate and nitrite sensing; PAS, Per-Arnt-Sim. Chemoreceptors are present in higher oligomeric states in vivo but are shown as monomers for simplicity. The assignment of P. aeruginosa PAO1 chemoreceptors to their respective chemosensory pathways was reported by Ortega et al. (10).