Differences in the Carboxy-Terminal (Putative Phospholipid Binding) Domains of Clostridium perfringens and Clostridium bifermentans Phospholipases C Influence the Hemolytic and Lethal Properties of These Enzymes

AUTOR(ES)

Jepson, Marie

FONTE

American Society for Microbiology

RESUMO

The phospholipases C of C. perfringens (alpha-toxin) and C. bifermentans (Cbp) show >50% amino acid homology but differ in their hemolytic and toxic properties. We report here the purification and characterisation of alpha-toxin and Cbp. The phospholipase C activity of alpha-toxin and Cbp was similar when tested with phosphatidylcholine in egg yolk or in liposomes. However, the hemolytic activity of alpha-toxin was more than 100-fold that of Cbp. To investigate whether differences in the carboxy-terminal domains of these proteins were responsible for differences in the hemolytic and toxic properties, a hybrid protein (NbiCα) was constructed comprising the N domain of Cbp and the C domain of alpha-toxin. The hemolytic activity of NbiCα was 10-fold that of Cbp, and the hybrid enzyme was toxic. These results confirm that the C-terminal domain of these proteins confers different properties on the enzymatically active N-terminal domain of these proteins.

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