Crystallization and preliminary X-ray crystallographic analysis of human quinolinate phosphoribosyltransferase

Quinolinate phosphoribosyltransferase (QPRTase) is a key NAD-biosynthetic enzyme which catalyzes the transfer of quinolinic acid to 5-phosphoribosyl-1-pyrophosphate, yielding nicotinic acid mononucleotide. Homo sapiens QPRTase (Hs-QPRTase) appeared as a hexamer during purification and the protein was crystallized. Diffraction data were collected and processed at 2.8 Å resolution. Native Hs-QPRTase crystals belonged to space group P2₁, with unit-cell parameters a = 76.2, b = 137.1, c = 92.7 Å, β = 103.8°. Assuming the presence of six molecules in the asymmetric unit, the calculated Matthews coefficient is 2.46 ų Da⁻¹, which corresponds to a solvent content of 49.9%.