Crystallization and preliminary X-ray diffraction analysis of P30, the transmembrane domain of pertactin, an autotransporter from Bordetella pertussis

P30, the 32 kDa transmembrane C-terminal domain of pertactin from Bordetella pertussis, is supposed to form a β-barrel inserted into the outer membrane for the translocation of the passenger domain. P30 was cloned and expressed in inclusion bodies in Escherichia coli. After refolding and purification, the protein was crystallized using the sitting-drop vapour-diffusion method at 292 K. The crystals diffract to a resolution limit of 3.5 Å using synchrotron radiation and belong to the hexagonal space group P6₁22, with unit-cell parameters a = b = 123.27, c = 134.43 Å.