Figure 9.

Interaction of C. perfringens α-toxin with the cell membrane. C. perfringens α-toxin is secreted as an inactive conformation. Binding to membrane phospholipid in a Ca⁺⁺-dependent manner induces a conformational change in loops 1 and 2, resulting in active toxin conformation. Hydrolysis of phosphatidylcholine and sphingomyelin at high toxin concentrations leads to membrane disruption. Inactive conformation, pdb 1QMD, and active conformation, pdb 1CA1; blue spheres, Ca⁺⁺. Figures were produced with the program MacPyMOL.