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 Å resolution in space group P212121, with unit‐cell parameters a = 38.68, b = 46.73, c = 88.9 Å.