FIGURE 3.

CdtABC preferentially associates with cholesterol and lipid rafts. LUVs were prepared containing either 13% (black bars) or 26% (gray bars) SM along with 20% cholesterol. The LUVs were assessed in real time for binding to immobilized Cdt. The maximum response units (mean ± S.D. of five experiments) is plotted versus Cdt concentration. The asterisk denotes a statistically significant difference between 13 and 26% sphingomyelin (p = 0.040); no significant difference was detected at the lower toxin concentrations.