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  • Pore formation by equinqtoxin, a eukaryotic pore-forming toxin, requires a flexible N-terminal region and a stable beta-sandwich
    Kristan, Katarina ...
    Actinoporins are eukaryotic pore-forming proteins that create 2-nm pores in natural and model lipid membranes by the self-association of four monomers. The regions that undergo conformational change ... and form part of the transmembrane pore are currently being defined. It was shown recently that theN-terminal region (residues 10-28) of equinatoxin, an actinoporin from Actinia equina, participates in building of the final pore wall. Assuming thatthe pore is formed solely by a polypeptide chain, other parts of the toxinshould constitute the conductive channel and here we searched for these regions by disulfide scanning mutagenesis. Only double cysteine mutants where the N-terminal segment 1-30 was attached to the (3-sandwich exhibited reduced hemolytic activity upon disulfide formation, showing that other parts of equinatoxin, particularly the beta-sandwich and importantly the C-terminal a-helix, do not undergo large conformational rearrangements during the pore formation.The role of the beta-sandwich stability was independently assessed via destabilization of a part of its hydrophobic core by mutations of the buried Trp117 These mutants were considerably less stable than the wild-type but exhibited similar or slightly lower permeabilizing activity. Collectively these results show that a flexible N-terminal region and stable beta-sandwich are pre-requisite for proper pore formation by the actinoporin family.
    Vir: The Journal of biological chemistry. - ISSN 0021-9258 (Letn. 279, št. 45, 2004, str. 46509-46517)
    Vrsta gradiva - članek, sestavni del
    Leto - 2004
    Jezik - angleški
    COBISS.SI-ID - 18475481

vir: The Journal of biological chemistry. - ISSN 0021-9258 (Letn. 279, št. 45, 2004, str. 46509-46517)
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