Characterization of TcdB C-terminal truncations.
A, schematic drawings of TcdB C-terminal truncated constructs, B2034 (TcdB1–2034), B1900 (TcdB1–1900), B1834 (TcdB1–1834), and CROP domain (TcdB1834–2366). B, interaction between truncated TcdB constructs and CSPG4. His-tagged TcdB constructs were incubated with lysate from cells overexpressing FLAG-tagged CSPG4 and subjected to immunoprecipitation (CO-IP) by anti-FLAG antibody and visualized by immunoblot as described. C, sensitivity of Vero and Caco-2 cells toward TcdB C-terminal truncations. Vero cells (left) and Caco-2 cells (right) were exposed to TcdB-truncated toxins, and cell survival was assessed by the SRB assay as previously described.