Expression, purification, crystallization and preliminary X-ray diffraction analysis of Deg5 from Arabidopsis thaliana

Arabidopsis thaliana Deg5 is an ATP-independent serine protease which resides on the luminal side of the thylakoid in chloroplasts. Deg5 and another Deg/HtrA-family protease, Deg8, have a synergistic function in the turnover of the D1 protein of photosystem II (PSII), which is prone to damage arising from high light exposure. An inactive mutant of the protein, Deg5^S266A, was overexpressed in Escherichia coli. After purification and crystallization, crystals that diffracted to 2.6 Å resolution were obtained. The crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 109.1, b = 126.0, c = 83.3 Å, β = 102.9°, and contained three molecules in the asymmetric unit. The calculated Matthews coefficient and solvent content were 3.0 ų Da⁻¹ and 59.0%, respectively.