Abstract
The protective antigen component of anthrax toxin forms a homoheptameric pore in the endosomal membrane, creating a narrow passageway for the enzymatic components of the toxin to enter the cytosol. We found that, during conversion of the heptameric precursor to the pore, the seven phenylalanine-427 residues converged within the lumen, generating a radially symmetric heptad of solvent-exposed aromatic rings. This "φ-clamp" structure was required for protein translocation and comprised the major conductance-blocking site for hydrophobic drugs and model cations. We conclude that the φ clamp serves a chaperone-like function, interacting with hydrophobic sequences presented by the protein substrate as it unfolds during translocation.
Original language | English (US) |
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Pages (from-to) | 777-781 |
Number of pages | 5 |
Journal | Science |
Volume | 309 |
Issue number | 5735 |
DOIs | |
State | Published - Jul 29 2005 |
ASJC Scopus subject areas
- General