Acta Crystallographica Section F

Structural Biology and Crystallization Communications

Volume 63, Part 1 (January 2007)

crystallization communications

Acta Cryst. (2007). F63, 15-17 [ doi:10.1107/S1744309106051578 ]

Purification, crystallization and preliminary crystallographic analysis of archaeal 6-pyruvoyl tetrahydrobiopterin synthase homologue PH0634 from Pyrococcus horikoshii OT3

B. Bagautdinov, M. Sugahara and N. Kunishima

Abstract: 6-Pyruvoyl tetrahydrobiopterin synthase (PTPS) catalyses the conversion of dihydroneopterin triphosphate to 6-pyruvoyl tetrahydropterin, the second of the three enzymatic steps in the synthesis of tetrahydrobiopterin from GTP. PH0634, a 13.51 kDa archaeal PTPS homologue from Pyrococcus horikoshii OT3, was overexpressed as native and selenomethionine-substituted protein and the purified protein was crystallized by the oil-microbatch method at 295 K. X-ray diffraction data were collected to 2.1 Å resolution from the native crystal using synchrotron radiation at 100 K. The crystal belongs to the orthorhombic space group P2₁2₁2₁, with unit-cell parameters a = 35.83, b = 95.71, c = 105.65 Å. Threefold noncrystallographic symmetry was identified from self-rotation calculations. Assuming the presence of a trimer in the asymmetric unit, the solvent content is 45% (V_M = 2.24 Å³ Da^-1). The selenomethionine-substituted crystal is isomorphous to the native crystal and diffracts X-rays to 2.9 Å.

Keywords: tetrahydrobiopterin biothynthesis; 6-pyruvoyl tetrahydrobiopterin synthase; Pyrococcus horikoshii OT3.