Author(s): Naylor CE, Eaton JT, Howells A, Justin N, Moss DS,
Abstract Share this page
Abstract Clostridium perfringens alpha-toxin is the key virulence determinant in gas gangrene and has also been implicated in the pathogenesis of sudden death syndrome in young animals. The toxin is a 370-residue, zinc metalloenzyme that has phospholipase C activity, and can bind to membranes in the presence of calcium. The crystal structure of the enzyme reveals a two-domain protein. The N-terminal domain shows an anticipated structural similarity to Bacillus cereus phosphatidylcholine-specific phospholipase C (PC-PLC). The C-terminal domain shows a strong structural analogy to eukaryotic calcium-binding C2 domains. We believe this is the first example of such a domain in prokaryotes. This type of domain has been found to act as a phospholipid and/or calcium-binding domain in intracellular second messenger proteins and, interestingly, these pathways are perturbed in cells treated with alpha-toxin. Finally, a possible mechanism for alpha-toxin attack on membrane-packed phospholipid is described, which rationalizes its toxicity when compared to other, non-haemolytic, but homologous phospholipases C.
This article was published in Nat Struct Biol
and referenced in Journal of Glycomics & Lipidomics