Phosphate-binding protein from Polaromonas JS666: purification, characterization, crystallization and sulfur SAD phasing

Acta Crystallogr F Struct Biol Commun. 2017 Jun 1;73(Pt 6):342-346. doi: 10.1107/S2053230X17007373. Epub 2017 May 25.


Phosphate-binding proteins (PBPs) are key proteins that belong to the bacterial ABC-type phosphate transporters. PBPs are periplasmic (or membrane-anchored) proteins that capture phosphate anions from the environment and release them to the transmembrane transporter. Recent work has suggested that PBPs have evolved for high affinity as well as high selectivity. In particular, a short, unique hydrogen bond between the phosphate anion and an aspartate residue has been shown to be critical for selectivity, yet is not strictly conserved in PBPs. Here, the PBP from Polaromonas JS666 is focused on. Interestingly, this PBP is predicted to harbor different phosphate-binding residues to currently known PBPs. Here, it is shown that the PBP from Polaromonas JS666 is capable of binding phosphate, with a maximal binding activity at pH 8. Its structure is expected to reveal its binding-cleft configuration as well as its phosphate-binding mode. Here, the expression, purification, characterization, crystallization and X-ray diffraction data collection to 1.35 Å resolution of the PBP from Polaromonas JS666 are reported.

Keywords: Polaromonas JS666; molecular specificity; phosphate ABC transporter; phosphate-binding protein.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Cloning, Molecular
  • Comamonadaceae / chemistry*
  • Comamonadaceae / metabolism
  • Crystallization
  • Crystallography, X-Ray
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Hydrogen Bonding
  • Hydrogen-Ion Concentration
  • Periplasm / chemistry*
  • Periplasm / metabolism
  • Phosphate-Binding Proteins / chemistry*
  • Phosphate-Binding Proteins / genetics
  • Phosphate-Binding Proteins / metabolism
  • Phosphates / chemistry*
  • Phosphates / metabolism
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • X-Ray Diffraction


  • Bacterial Proteins
  • Phosphate-Binding Proteins
  • Phosphates
  • Recombinant Fusion Proteins