Purification, crystallization and preliminary X-ray diffraction study on pyrimidine nucleoside phosphorylase TTHA1771 from Thermus thermophilus HB8

Pyrimidine nucleoside phosphorylase (PYNP) catalyzes the reversible phosphorolysis of pyrimidines in the nucleotide-synthesis salvage pathway. In order to study the structure–thermostability relationship of this enzyme, PYNP from the extreme thermophile Thermus thermophilus HB8 (TTHA1771) has been cloned, overexpressed and purified. The TTHA1771 protein was crystallized at 291 K using the oil-microbatch method with PEG 4000 as a precipitant. A native data set was collected to 1.8 Å resolution using synchrotron radiation. The crystal belongs to the monoclinic space group P2₁, with unit-cell parameters a = 58.83, b = 76.23, c = 103.86 Å, β = 91.3°.