title: Cytotoxin ClyA from Escherichia coli assembles to a 13-meric pore independent of its redox-state.
abstract: 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 A 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.
authors: Maurice E Müller Institute for Microscopy, Biozentrum, University of Basel, Basel, Switzerland.
authors: Nora
authors: N
authors: Eifler
authors: Michael
authors: M
authors: Vetsch
authors: Marco
authors: M
authors: Gregorini
authors: Philippe
authors: P
authors: Ringler
authors: Mohamed
authors: M
authors: Chami
authors: Ansgar
authors: A
authors: Philippsen
authors: Andrea
authors: A
authors: Fritz
authors: Shirley A
authors: SA
authors: Müller
authors: Rudi
authors: R
authors: Glockshuber
authors: Andreas
authors: A
authors: Engel
authors: Ulla
authors: U
authors: Grauschopf