Recombinant expression and purification of the tomato defensin TPP3 and its preliminary X-ray crystallographic analysis

Class II defensins have been shown to have potent antifungal activity and are being exploited to protect agricultural crops against fungal pathogens. TPP3 is a poorly characterized member of the class II plant defensin family from tomato. To gain structural insight into the function of TPP3, soluble recombinant TPP3 was expressed and purified using the Pichia pastoris expression system, and the crystallization and preliminary X-ray crystallographic analysis of the protein are reported. Crystals of rTPP3 were obtained using the sitting-drop vapour-diffusion method at 293 K. Diffraction data were collected to 1.7 Å resolution. The crystals belonged to the hexagonal space group P6₁22, with unit-cell parameters a = 64.97, b = 64.97, c = 82.40 Å, α = 90, β = 90, γ = 120°.