The role of the serine protease active site in the mode of action of epidermolytic toxin of<i>Staphylococcus aureus</i>

Abstract

The sequences of the epidermolytic toxins and V8 serine proteinase share about 25% identity, including the catalytic triad at the proteinase active centre. Here we have altered the putative ETA active-site serine-195 to glycine by site-directed mutagenesis. No epidermolytic activity was detected when up to 100-fold greater amounts of the homogeneous mutant ETA were injected subcutaneously into neonatal mice showing that serine-195 is required for toxicogenesis.