title: Preliminary X-ray crystallographic study of staphylococcal α-haemolysin monomer.
abstract: Staphylococcal α-haemolysin is a β-barrel pore-forming toxin expressed by Staphylococcus aureus. α-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 α-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, α-haemolysin H35A mutants were expressed, purified and crystallized. Diffraction data were collected to 2.90 Å resolution. The crystals belonged to space group P6₁, 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 α-haemolysin.
authors.affiliation: School of Sciences, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Takaki
authors.initials: T
authors.lastname: Sugawara
authors.forename: Daichi
authors.initials: D
authors.lastname: Yamashita
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Jun
authors.initials: J
authors.lastname: Kaneko
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kamio
authors.forename: Isao
authors.initials: I
authors.lastname: Tanaka
authors.forename: Min
authors.initials: M
authors.lastname: Yao
mesh_terms: D000409:Alanine / Q000235:genetics; D001427:Bacterial Toxins / Q000737:chemistry* / Q000235:genetics; D018360:Crystallography, X-Ray; D006460:Hemolysin Proteins / Q000737:chemistry* / Q000235:genetics; D006639:Histidine / Q000235:genetics; D009154:Mutation / Q000235:genetics; D013208:Staphylococcal Toxoid / Q000737:chemistry* / Q000235:genetics
chemical_list: D001427:Bacterial Toxins; D006460:Hemolysin Proteins; D013208:Staphylococcal Toxoid; C021091:staphylococcal alpha-toxin; D006639:Histidine; D000409:Alanine
keywords: monomer; pore-forming toxins; staphylococcal α-haemolysin
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