Preliminary X-ray crystallographic study of staphylococcal ?-haemolysin monomer.

ABSTRACT: Staphylococcal ?-haemolysin is a ?-barrel pore-forming toxin expressed by Staphylococcus aureus. ?-Haemolysin is secreted as a water-soluble monomeric protein which binds to target membranes and forms membrane-inserted heptameric pores. Although the crystal structures of the heptameric pore and monomer bound to an antibody have been determined, that of monomeric ?-haemolysin without binder has yet to be elucidated. Previous mutation studies showed that mutants of His35 retain the monomeric structure but are unable to assemble into heptamers. Here, ?-haemolysin H35A mutants were expressed, purified and crystallized. Diffraction data were collected to 2.90 Å resolution. The crystals belonged to space group P6?, with unit-cell parameters a = b = 151.3, c = 145.0 Å. Molecular replacement found four molecules in an asymmetric unit. The relative orientation among molecules was distinct from that of the pore, indicating that the crystal contained monomeric ?-haemolysin.

SUBMITTER: Sugawara T 

PROVIDER: S-EPMC3729161 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature