Abstract
The α-hemolysin is an archetypal pore-forming protein that is secreted from Staphylococcus aureus as a water-soluble monomer. When the monomer binds to the membrane of a susceptible cell, the membrane-bound molecules assemble into the lytic heptamer. Although a bilayer or a bilayer-like environment are essential to toxin assembly, there is no high resolution information on toxin-phospholipid complexes. We have determined the structures of detergent-solubilized α-hemolysin heptamer bound to glycerophosphocholine or dipropanoyl glycerophosphocholine at 1.75-1.80 Å resolution and 110 K. The phosphocholine head group binds to each subunit in a crevice between the rim and the stem domains. The quaternary ammonium group interacts primarily with aromatic residues, whereas the phosphodiester moiety interacts with a conserved arginine residue. These structures provide a molecular basis for understanding why α-hemolysin preferentially assembles on membranes comprised of phosphocholine lipids.
Original language | English (US) |
---|---|
Pages (from-to) | 1503-1511 |
Number of pages | 9 |
Journal | Protein Science |
Volume | 13 |
Issue number | 6 |
DOIs | |
State | Published - Jun 2004 |
Externally published | Yes |
Keywords
- Integral membrane protein
- Pore-forming toxin
- Protein-membrane interactions
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology