title: Crystal structure of the octameric pore of staphylococcal γ-hemolysin reveals the β-barrel pore formation mechanism by two components.
abstract: Staphylococcal γ-hemolysin is a bicomponent pore-forming toxin composed of LukF and Hlg2. These proteins are expressed as water-soluble monomers and then assemble into the oligomeric pore form on the target cell. Here, we report the crystal structure of the octameric pore form of γ-hemolysin at 2.5 Å resolution, which is the first high-resolution structure of a β-barrel transmembrane protein composed of two proteins reported to date. The octameric assembly consists of four molecules of LukF and Hlg2 located alternately in a circular pattern, which explains the biochemical data accumulated over the past two decades. The structure, in combination with the monomeric forms, demonstrates the elaborate molecular machinery involved in pore formation by two different molecules, in which interprotomer electrostatic interactions using loops connecting β2 and β3 (loop A: Asp43-Lys48 of LukF and Lys37-Lys43 of Hlg2) play pivotal roles as the structural determinants for assembly through unwinding of the N-terminal β-strands (amino-latch) of the adjacent protomer, releasing the transmembrane stem domain folded into a β-sheet in the monomer (prestem), and interaction with the adjacent protomer.
authors.affiliation: Graduate School of Life Science , Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Yamashita
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kawai
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Nagisa
authors.initials: N
authors.lastname: Hirano
authors.forename: Jun
authors.initials: J
authors.lastname: Kaneko
authors.forename: Noriko
authors.initials: N
authors.lastname: Tomita
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohta
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kamio
authors.forename: Min
authors.initials: M
authors.lastname: Yao
authors.forename: Isao
authors.initials: I
authors.lastname: Tanaka
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D001427:Bacterial Toxins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006460:Hemolysin Proteins / Q000737:chemistry*; D007956:Leukocidins / Q000737:chemistry; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000737:chemistry; D013211:Staphylococcus aureus / Q000737:chemistry / Q000472:pathogenicity; D055672:Static Electricity
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D006460:Hemolysin Proteins; C503458:Hlg2 protein, Staphylococcus; D007956:Leukocidins; D046912:Multiprotein Complexes; D021122:Protein Subunits; D011994:Recombinant Proteins; C037956:gamma-hemolysin, Staphylococcus aureus; C074300:LukF protein, Staphylococcus aureus