title: Distinction between pore assembly by staphylococcal alpha-toxin versus leukotoxins.
abstract: The staphylococcal bipartite leukotoxins and the homoheptameric alpha-toxin belong to the same family of beta-barrel pore-forming toxins despite slight differences. In the alpha-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 beta-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 beta-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 alpha-toxin.
authors.affiliation: Laboratoire de Physiopathologie et d'Antibiologie des Infections Bactériennes Emergentes et Nosocomiales, EA 3432, Institut de Bactériologie de la Faculté de Médecine, Université Louis Pasteur-Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Joubert
authors.forename: Joëlle
authors.initials: J
authors.lastname: Voegelin
authors.forename: Valérie
authors.initials: V
authors.lastname: Guillet
authors.forename: Samuel
authors.initials: S
authors.lastname: Tranier
authors.forename: Sandra
authors.initials: S
authors.lastname: Werner
authors.forename: Didier A
authors.initials: DA
authors.lastname: Colin
authors.forename: Mauro
authors.initials: M
authors.lastname: Dalla Serra
authors.forename: Daniel
authors.initials: D
authors.lastname: Keller
authors.forename: Henri
authors.initials: H
authors.lastname: Monteil
authors.forename: Lionel
authors.initials: L
authors.lastname: Mourey
authors.forename: Gilles
authors.initials: G
authors.lastname: Prévost