Expression, purification, crystallization and preliminary X-ray diffraction analysis of a core fragment of FlgG, a bacterial flagellar rod protein

FlgG is a bacterial flagellar rod protein and constructs the distal rod connecting to the hook. FlgG of Salmonella enterica serovar Typhimurium is a 260-amino-acid protein composed of a folded core region and N- and C-terminal regions that are unfolded in solution. A core fragment of FlgG (FlgG_47-227) was expressed, purified and crystallized. Crystals of native and SeMet-labelled FlgG_47-227 were obtained by the sitting-drop vapour-diffusion technique with PEG MME 2000 as precipitant. The native crystal belonged to the primitive orthorhombic space group P2₁2₁2₁, with unit-cell parameters a = 47.78, b = 68.94, c = 110.57 Å. The SeMet crystal also belonged to space group P2₁2₁2₁, with unit-cell parameters a = 47.53, b = 67.04, c = 110.27 Å.