Crystallization and preliminary crystallographic characterization of the extrinsic PsbP protein of photosystem II from Spinacia oleracea

Preliminary X-ray diffraction analysis of the extrinsic PsbP protein of photosystem II from spinach (Spinacia oleracea) was performed using N-­terminally His-tagged recombinant PsbP protein overexpressed in Escherichia coli. Recombinant PsbP protein (thrombin-digested recombinant His-tagged PsbP) stored in bis-Tris buffer pH 6.00 was crystallized using the sitting-drop vapour-diffusion technique with PEG 550 MME as a precipitant and zinc sulfate as an additive. SDS–PAGE analysis of a dissolved crystal showed that the crystals did not contain the degradation products of recombinant PsbP protein. PsbP crystals diffracted to 2.06 A resolution in space group P212121, with unit-cell parameters a = 38.68, b = 46.73, c = 88.9 A.