FIG 8.

Truncations of the TpeL toxin lead to loss of secretion. (A) Diagram showing the location of specific domains in the TpeL protein. A, glycosyltransferase domain; C, autocatalytic protease domain; D, delivery domain; B, receptor domain. A table listing the TpeL truncations used and their respective molecular weights is included. (B) Western blot showing the intracellular levels and secretion of full-length and truncated TpeL. An anti-His₆ antibody was used to detect each form of the protein. Note the absence of the streptavidin-BCP lysis control signal in the supernatant fractions, indicating that very little lysis had occurred. (C) Growth curves showing that strains expressing truncated TpeL proteins (pAS42, pAS43, and pAS44) do not have defects in their growth in comparison to strains expressing full-length TpeL (pAS11 and pAS45). The means and standard errors of the means (SEM) from five replicate samples are shown. The curves are representative of results from three independent biological replicates.