Distinction between Pore Assembly by Staphylococcal α-Toxin versus Leukotoxins

• Main Authors: Olivier Joubert, Joëlle Voegelin, Valérie Guillet, Samuel Tranier, Sandra Werner, Didier A. Colin, Mauro Dalla Serra, Daniel Keller, Henri Monteil, Lionel Mourey, Gilles Prévost
• Format: Article
• Language: English
• Published: Hindawi Limited 2007-01-01
• Series: Journal of Biomedicine and Biotechnology
• Online Access: http://dx.doi.org/10.1155/2007/25935

The staphylococcal bipartite leukotoxins and the homoheptameric α-toxin belong to the same family of β-barrel pore-forming toxins despite slight differences. In the α-toxin pore, the N-terminal extremity of each protomer interacts as a deployed latch with two consecutive protomers in the vicinity of the pore lumen. N-terminal extremities of leukotoxins as seen in their three-dimensional structures are heterogeneous in length and take part in the β-sandwich core of soluble monomers. Hence, the interaction of these N-terminal extremities within structures of adjacent monomers is questionable. We show here that modifications of their N-termini by two different processes, using fusion with glutathione S-transferase (GST) and bridging of the N-terminal extremity to the adjacent β-sheet via disulphide bridges, are not deleterious for biological activity. Therefore, bipartite leukotoxins do not need a large extension of their N-terminal extremities to form functional pores, thus illustrating a microheterogeneity of the structural organizations between bipartite leukotoxins and α-toxin.