title: Structural characterization of outer membrane components of the type IV pili system in pathogenic Neisseria.
abstract: Structures of the type IV pili secretin complexes from Neisseria gonorrhoeae and Neisseria meningitidis, embedded in outer membranes were investigated by transmission electron microscopy. Single particle averaging revealed additional domains not observed previously. Secretin complexes of N. gonorrhoeae showed a double ring structure with a 14-15-fold symmetry in the central ring, and a 14-fold symmetry of the peripheral ring with 7 spikes protruding. In secretin complexes of N. meningitidis, the spikes were absent and the peripheral ring was partly or completely lacking. When present, it had a 19-fold symmetry. The structures of the complexes in several pil mutants were determined. Structures obtained from the pilC1/C2 adhesin and the pilW minor pilin deletion strains were similar to wild-type, whereas deletion of the homologue of N. meningitidis PilW resulted in the absence of secretin structures. Remarkably, the pilE pilin subunit and pilP lipoprotein deletion mutants showed a change in the symmetry of the peripheral ring from 14 to 19 and loss of spikes. The pilF ATPase mutant also lost the spikes, but maintained 14-fold symmetry. These results show that secretin complexes contain previously unidentified large and flexible extra domains with a probable role in stabilization or assembly of type IV pili.
authors.affiliation: Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute and the Zernike Institute for Advanced Materials, University of Groningen, Haren, The Netherlands.
authors.forename: Samta
authors.initials: S
authors.lastname: Jain
authors.forename: Katarzyna B
authors.initials: KB
authors.lastname: Mościcka
authors.forename: Martine P
authors.initials: MP
authors.lastname: Bos
authors.forename: Emilia
authors.initials: E
authors.lastname: Pachulec
authors.forename: Marc C A
authors.initials: MC
authors.lastname: Stuart
authors.forename: Wilko
authors.initials: W
authors.lastname: Keegstra
authors.forename: Egbert J
authors.initials: EJ
authors.lastname: Boekema
authors.forename: Chris
authors.initials: C
authors.lastname: van der Does
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000648:ultrastructure; D001426:Bacterial Proteins; D036781:Fimbriae Proteins / Q000737:chemistry* / Q000648:ultrastructure; D010861:Fimbriae, Bacterial / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D046912:Multiprotein Complexes / Q000737:chemistry; D009343:Neisseria / Q000737:chemistry*; D009344:Neisseria gonorrhoeae / Q000737:chemistry; D009345:Neisseria meningitidis / Q000737:chemistry; D011487:Protein Conformation
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D046912:Multiprotein Complexes; C074063:pilE protein, Neisseria gonorrhoeae; C081816:pilF protein, Neisseria; D036781:Fimbriae Proteins