Crystallization of the α-hemolysin heptamer solubilized in decyldimethyl- and decyldiethylphosphine oxide

Crystals of the α-hemolysin heptamer, a transmembrane pore-forming toxin from Staphylococcus aureus, have been grown using the nonionic detergents n-decyldimethyl- and n-decyldiethylphosphine oxide, phosphorus homologs of the ionic amine oxide detergents. Five crystal forms were obtained, one of which diffracted X-rays to 3 Å resolution. This crystal form displayed elements of pseudo mm symmetry in screened precession photographs yet it was triclinic with unit-cell dimensions a = 173, b = 173, c = 102 Å, α = 92.6, β = 94.8, γ = 90.2°.