title: Structure and biogenesis of the capsular F1 antigen from Yersinia pestis: preserved folding energy drives fiber formation.
abstract: Most gram-negative pathogens express fibrous adhesive virulence organelles that mediate targeting to the sites of infection. The F1 capsular antigen from the plague pathogen Yersinia pestis consists of linear fibers of a single subunit (Caf1) and serves as a prototype for nonpilus organelles assembled via the chaperone/usher pathway. Genetic data together with high-resolution X-ray structures corresponding to snapshots of the assembly process reveal the structural basis of fiber formation. Comparison of chaperone bound Caf1 subunit with the subunit in the fiber reveals a novel type of conformational change involving the entire hydrophobic core of the protein. The observed conformational change suggests that the chaperone traps a high-energy folding intermediate of Caf1. A model is proposed in which release of the subunit allows folding to be completed, driving fiber formation.
authors.affiliation: Department of Molecular Biosciences/Structural Biology, Uppsala Biomedical Center, Swedish University of Agricultural Sciences, Box 590, SE-751 24 Uppsala, Sweden.
authors.forename: Anton V
authors.initials: AV
authors.lastname: Zavialov
authors.forename: Jenny
authors.initials: J
authors.lastname: Berglund
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Pudney
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Fooks
authors.forename: Tara M
authors.initials: TM
authors.lastname: Ibrahim
authors.forename: Sheila
authors.initials: S
authors.lastname: MacIntyre
authors.forename: Stefan D
authors.initials: SD
authors.lastname: Knight
mesh_terms: D000942:Antigens, Bacterial / Q000096:biosynthesis* / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed / Q000235:genetics; D015388:Organelles / Q000378:metabolism*; D017510:Protein Folding; D020836:Protein Structure, Quaternary / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D015010:Yersinia pestis / Q000235:genetics / Q000378:metabolism*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D018832:Molecular Chaperones; C086725:caf1 protein, Yersinia pestis; D003545:Cysteine