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

Area of Science:

• Biochemistry
• Structural Biology
• Microbiology

Background:

• Phosphate-binding proteins (PBPs) are crucial components of bacterial ABC-type phosphate transporters.
• PBPs are periplasmic or membrane-anchored proteins responsible for capturing environmental phosphate anions.
• Recent studies indicate PBPs possess high affinity and selectivity for phosphate, with a key hydrogen bond for selectivity, though not universally conserved.

Purpose of the Study:

• To investigate the PBP from Polaromonas JS666, which is predicted to have distinct phosphate-binding residues.
• To characterize the phosphate-binding activity and optimal conditions for the PBP from Polaromonas JS666.
• To determine the structure of the PBP from Polaromonas JS666 to understand its binding-cleft configuration and phosphate-binding mode.

Main Methods:

• Expression and purification of the PBP from Polaromonas JS666.
• Characterization of phosphate-binding activity, including pH optimum determination.
• Crystallization and X-ray diffraction data collection to 1.35 Å resolution.

Main Results:

• The PBP from Polaromonas JS666 demonstrates phosphate-binding capability.
• Maximal phosphate-binding activity for this PBP occurs at pH 8.
• High-resolution (1.35 Å) X-ray diffraction data have been collected.

Conclusions:

• The PBP from Polaromonas JS666 functions in phosphate transport and exhibits unique predicted binding residues.
• The optimal activity at pH 8 provides insights into its functional environment.
• The determined structure is anticipated to reveal novel mechanisms of phosphate binding and selectivity in bacterial transporters.