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Journal of Biomedicine and Biotechnology
Volume 2007 (2007), Article ID 25935, 13 pages
http://dx.doi.org/10.1155/2007/25935
Research Article

Distinction between Pore Assembly by Staphylococcal α-Toxin versus Leukotoxins

1Laboratoire 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, 3 Rue Koeberlé, Strasbourg 67000, France
2Groupe de Biophysique Structurale, Département Mécanismes Moléculaires des Infections Mycobactériennes, Institut de Pharmacologie et de Biologie Structurale (IPBS), CNRS-UMR 5089, 205 Route de Narbonne, Toulouse Cedex 31077, France
3Société Parogène, Faculté de Médecine et d'Odontologie, Université Louis Pasteur-Hôpitaux Universitaires de Strasbourg, 11 Rue Humann, Strasbourg Cedex 67085, France
4Istituto di BioFisica (IBF), Consiglio Nazionale delle Richerche (CNR), Via Sommarive 18, Povo, Trento 38050, Italy

Received 10 August 2006; Revised 7 November 2006; Accepted 6 December 2006

Academic Editor: Shahid Jameel

Copyright © 2007 Olivier Joubert et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

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.