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Cytotoxin ClyA from Escherichia coli assembles to a 13‐meric pore independent of its redox‐state
Author(s) -
Eifler Nora,
Vetsch Michael,
Gregorini Marco,
Ringler Philippe,
Chami Mohamed,
Philippsen Ansgar,
Fritz Andrea,
Müller Shirley A,
Glockshuber Rudi,
Engel Andreas,
Grauschopf Ulla
Publication year - 2006
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7601130
Subject(s) - biology , escherichia coli , escherichia coli proteins , redox , bacterial protein , enterobacteriaceae , microbiology and biotechnology , biophysics , biochemistry , bacteria , genetics , gene , materials science , metallurgy
ClyA is a pore‐forming toxin from virulent Escherichia coli and Salmonella enterica strains. Here, we show that the intrinsic hemolytic activity of ClyA is independent of its redox state, and that the assembly of both reduced and oxidized ClyA to the ring‐shaped oligomer is triggered by contact with lipid or detergent. A rate‐limiting conformational transition in membrane‐bound ClyA monomers precedes their assembly to the functional pore. We obtained a three‐dimensional model of the detergent‐induced oligomeric complex at 12 Å resolution by combining cryo‐ and negative stain electron microscopy with mass measurements by scanning transmission electron microscopy. The model reveals that 13 ClyA monomers assemble into a cylinder with a hydrophobic cap region, which may be critical for membrane insertion.