Crystal structure of E. coli PRPP synthetase.

Area of Science:

• Biochemistry
• Structural Biology
• Enzymology

Background:

• Ribose-phosphate pyrophosphokinase (EC 2.7.6.1) is essential for nucleotide biosynthesis.
• It catalyzes the conversion of ribose-5-phosphate to phosphoribosyl pyrophosphate, a key precursor for purine and pyrimidine nucleotides.

Purpose of the Study:

• To determine the crystal structure of E. coli ribose-phosphate pyrophosphokinase (EcKPRS).
• To elucidate the structural basis for its enzymatic activity and potential regulation.

Main Methods:

• X-ray crystallography was used to obtain the 2.2 Å crystal structure of EcKPRS.
• Structural analysis focused on active site residues, substrate binding, and allosteric site conformation.

Main Results:

• EcKPRS forms a homohexameric propeller structure composed of a trimer of dimers.
• The structure reveals well-defined active site residues for substrate binding (adenosine monophosphate and ribose-5-phosphate).
• A flexible loop occupies the allosteric site, potentially regulating modulator binding.

Conclusions:

• The study provides key structural insights into EcKPRS, an enzyme critical for nucleotide metabolism.
• The findings offer a structural framework for future research and potential development of antibacterial agents targeting nucleotide biosynthesis.