Abstract
The 3.35 Å resolution crystal structure of a mutant form of the staphylococcal sphingomyelinase Β toxin in which a conserved hydrophobic Β-hairpin has been deleted is reported. It is shown that this mutation induces domain swapping of a C-terminal Β-strand, leading to the formation of dimers linked by a conformationally flexible hinge region. Eight dimers are seen in the asymmetric unit, exhibiting a broad spectrum of conformations trapped in place by intermolecular contacts within the crystal lattice. Furthermore, the 16 monomers within each asymmetric unit exhibit a remarkable heterogeneity in thermal factors, which can be accounted for by the varying degrees to which each monomer interacts with other molecules in the crystal. This structure provides a unique example of the challenges associated with crystallographic study of flexible proteins.
Original language | English (US) |
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Pages (from-to) | 438-441 |
Number of pages | 4 |
Journal | Acta Crystallographica Section F: Structural Biology and Crystallization Communications |
Volume | 67 |
Issue number | 4 |
DOIs | |
State | Published - Apr 2011 |
Keywords
- Staphylococcus aureus
- domain swapping
- sphingomyelinase
- Β toxin