AutoriG. Viero;a* A. Gropuzzo;a O. Joubert;b+ D. Keller;b G. Prevost;b and M. Dalla Serra;a
Abstractgamma-Hemolysins are pore-forming toxins which develop from water-soluble monomers by combining two different 'albeit homologous' proteins. They form oligomeric pores in both cell and model membranes by undergoing a still poorly understood conformational rearrangement in the stem region. The stem is formed by three beta-strands, folded onto the core of the soluble protein and completely extended in the pore. We propose a new model to explain such a process. Seven double-cysteine mutants were developed by inserting one cysteine on the stretch that links the beta-hairpin to the core of the protein and another on different positions along the beta-strands. The membrane bound protein was blocked in a non-lytic state by S-S bond formation. Six mutants were oxidized as inactive intermediates, but became active after adding DTT. These results demonstrate that the stem extension can be temporarily frozen and that the beta-barrel formation occurs by beta-strand concerted step-by-step sliding.
RivistaCellular And Molecular Life Sciences (print. Ed.)
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Pagina inizio312
Pagina fine323
Autori IBFMauro DALLA SERRA, Gabriella VIERO
Linee di Ricerca IBFMD.P01.001.001