Expression, purification, crystallization and preliminary crystallographic analysis of a putative Clostridium difficile surface protein Cwp19

Cwp19 is a putatively surface-located protein from Clostridium difficile. A recombinant N-terminal protein (residues 27–401) lacking the signal peptide and the C-terminal cell-wall-binding repeats (PFam04122) was crystallized using the sitting-drop vapour-diffusion method and diffracted to 2 Å resolution. The crystal appeared to belong to the primitive monoclinic space group P2(1), with unit-cell parameters a = 109.1, b = 61.2, c = 109.2 Å, β = 111.85°, and is estimated to contain two molecules of Cwp19 per asymmetric unit.