title: Structure of the bundle-forming pilus from enteropathogenic Escherichia coli.
abstract: Bundle-forming pili (BFP) are essential for the full virulence of enteropathogenic Escherichia coli (EPEC) because they are required for localized adherence to epithelial cells and auto-aggregation. We report the high resolution structure of bundlin, the monomer of BFP, solved by NMR. The structure reveals a new variation in the topology of type IVb pilins with significant differences in the composition and relative orientation of elements of secondary structure. In addition, the structural parameters of native BFP filaments were determined by electron microscopy after negative staining. The solution structure of bundlin was assembled according to these helical parameters to provide a plausible atomic resolution model for the BFP filament. We show that EPEC and Vibriocholerae type IVb pili display distinct differences in their monomer subunits consistent with data showing that bundlin and TcpA cannot complement each other, but assemble into filaments with similar helical organization.
authors.affiliation: Department of Biological Sciences, Wolfson Laboratory, Imperial College, London SW72AZ, United Kingdom.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Ramboarina
authors.forename: Paula J
authors.initials: PJ
authors.lastname: Fernandes
authors.forename: Sarah
authors.initials: S
authors.lastname: Daniell
authors.forename: Suhail
authors.initials: S
authors.lastname: Islam
authors.forename: Pete
authors.initials: P
authors.lastname: Simpson
authors.forename: Gad
authors.initials: G
authors.lastname: Frankel
authors.forename: Frank
authors.initials: F
authors.lastname: Booy
authors.forename: Michael S
authors.initials: MS
authors.lastname: Donnenberg
authors.forename: Stephen
authors.initials: S
authors.lastname: Matthews
mesh_terms: D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000737:chemistry; D010861:Fimbriae, Bacterial / Q000378:metabolism / Q000502:physiology*; D005583:Fourier Analysis; D007091:Image Processing, Computer-Assisted; D009682:Magnetic Resonance Spectroscopy; D008854:Microscopy, Electron; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012984:Software; D014734:Vibrio cholerae / Q000378:metabolism
chemical_list: C085807:TcpA protein, Vibrio cholerae; D036781:Fimbriae Proteins