Purification, crystallization and X-ray crystallographic analysis of the type VI secretion system accessory protein TagF from Pseudomonas aeruginosa

TagF is the product of the type VI secretion system (T6SS) accessory gene F, which is capable of regulating T6SS assembly in Pseudomonas aeruginosa. Experimental results suggest that TagF may post-translationally regulate the T6SS through phosphatase activity, but the physiological functions of TagF are not yet understood. To provide structural insight into TagF function and the regulatory mechanisms controlling the T6SS, N-terminally His 6 -tagged TagF was overexpressed, purified, and crystallized using hanging-drop vapor diffusion in a solution of 2.5 M NaCl and 0.1 M Bis-Tris propane (pH 7.0). X-ray diffraction data from TagF crystals was collected at a resolution of 2.7 Å. TagF crystals belonged to the space group P2 1 2 1 2, with unit cell parameters a = 93.7, b = 92.4, c = 151.1 Å, and α = β = γ = 90°. TagF consists of four independent subunits in the asymmetric unit.