Fig. 1

Conformational signaling model for control of the Pho regulon. a As the Pst transporter alternates between its inward and outward-facing conformations during Pi transport, it directly interacts with PhoR and PhoU. The inward facing conformation, which is stabilized by the pstBQ160K mutation, interacts with PhoR to stabilize its phosphatase conformation (light blue) while the outward conformation, which is stabilized by the pstBE179Q mutation, favors the kinase conformation of PhoR (green). b Sequence alignment of PstB and MalK performed by the European Molecular Biology Open Software Suite (EMBOSS). The mutated residues are marked with red stars. The Walker A, Walker B and the ABC Signature motifs are highlighted by green boxes. Amino acid identities are shows by vertical lines and conserved residues are shown by dots. c A three-dimensional model of the PstB homodimer created using the SWISS-MODEL website. The Q160 and E179 amino acid residues of PstB are highlighted. The Q160 and E179 residues are located on the dimer interface and are normally involved in ATP binding and hydrolysis