title: Neisseria meningitidis Type IV Pili Composed of Sequence Invariable Pilins Are Masked by Multisite Glycosylation.
abstract: The ability of pathogens to cause disease depends on their aptitude to escape the immune system. Type IV pili are extracellular filamentous virulence factors composed of pilin monomers and frequently expressed by bacterial pathogens. As such they are major targets for the host immune system. In the human pathogen Neisseria meningitidis, strains expressing class I pilins contain a genetic recombination system that promotes variation of the pilin sequence and is thought to aid immune escape. However, numerous hypervirulent clinical isolates express class II pilins that lack this property. This raises the question of how they evade immunity targeting type IV pili. As glycosylation is a possible source of antigenic variation it was investigated using top-down mass spectrometry to provide the highest molecular precision on the modified proteins. Unlike class I pilins that carry a single glycan, we found that class II pilins display up to 5 glycosylation sites per monomer on the pilus surface. Swapping of pilin class and genetic background shows that the pilin primary structure determines multisite glycosylation while the genetic background determines the nature of the glycans. Absence of glycosylation in class II pilins affects pilus biogenesis or enhances pilus-dependent aggregation in a strain specific fashion highlighting the extensive functional impact of multisite glycosylation. Finally, molecular modeling shows that glycans cover the surface of class II pilins and strongly decrease antibody access to the polypeptide chain. This strongly supports a model where strains expressing class II pilins evade the immune system by changing their sugar structure rather than pilin primary structure. Overall these results show that sequence invariable class II pilins are cloaked in glycans with extensive functional and immunological consequences.
authors.affiliation: Structural Mass Spectrometry and Proteomics Unit, Institut Pasteur, CNRS UMR 3528, Paris, France.
authors.forename: Joseph
authors.initials: J
authors.lastname: Gault
authors.affiliation: Institut Pasteur, Unité de Bioinformatique Structurale, CNRS UMR 3528, Département de Biologie Structurale et Chimie, Paris, France.
authors.forename: Mathias
authors.initials: M
authors.lastname: Ferber
authors.affiliation: INSERM, U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Faculté de Médecine Paris Descartes, Paris, France.
authors.forename: Silke
authors.initials: S
authors.lastname: Machata
authors.affiliation: INSERM, U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Faculté de Médecine Paris Descartes, Paris, France.
authors.forename: Anne-Flore
authors.initials: AF
authors.lastname: Imhaus
authors.affiliation: Structural Mass Spectrometry and Proteomics Unit, Institut Pasteur, CNRS UMR 3528, Paris, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Malosse
authors.affiliation: INSERM, U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Faculté de Médecine Paris Descartes, Paris, France.
authors.forename: Arthur
authors.initials: A
authors.lastname: Charles-Orszag
authors.affiliation: INSERM, U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Faculté de Médecine Paris Descartes, Paris, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Millien
authors.affiliation: Institut Pasteur, Unité de Bioinformatique Structurale, CNRS UMR 3528, Département de Biologie Structurale et Chimie, Paris, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Bouvier
authors.affiliation: Institut Pasteur, Unité de Bioinformatique Structurale, CNRS UMR 3528, Département de Biologie Structurale et Chimie, Paris, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Bardiaux
authors.affiliation: CNRS, UMR3528, Paris, France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Péhau-Arnaudet
authors.affiliation: Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America.
authors.forename: Kelly
authors.initials: K
authors.lastname: Klinge
authors.affiliation: Service de Microbiologie, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Podglajen
authors.affiliation: INSERM UMR1092, Faculté de Médecine, Université de Limoges, Limoges, France.
authors.forename: Marie Cécile
authors.initials: MC
authors.lastname: Ploy
authors.affiliation: Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America.
authors.forename: H Steven
authors.initials: HS
authors.lastname: Seifert
authors.affiliation: Institut Pasteur, Unité de Bioinformatique Structurale, CNRS UMR 3528, Département de Biologie Structurale et Chimie, Paris, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Nilges
authors.affiliation: Structural Mass Spectrometry and Proteomics Unit, Institut Pasteur, CNRS UMR 3528, Paris, France.
authors.forename: Julia
authors.initials: J
authors.lastname: Chamot-Rooke
authors.affiliation: INSERM, U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Faculté de Médecine Paris Descartes, Paris, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Duménil
mesh_terms: D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D002460:Cell Line; D002478:Cells, Cultured; D017124:Conserved Sequence; D004730:Endothelium, Vascular / Q000166:cytology / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D036781:Fimbriae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010861:Fimbriae, Bacterial / Q000276:immunology / Q000378:metabolism* / Q000648:ultrastructure; D017353:Gene Deletion; D006031:Glycosylation; D054884:Host-Pathogen Interactions; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D006801:Humans; D057131:Immune Evasion; D008589:Meningococcal Infections / Q000276:immunology / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D009345:Neisseria meningitidis / Q000276:immunology / Q000378:metabolism* / Q000648:ultrastructure; D011499:Protein Processing, Post-Translational; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013499:Surface Properties
chemical_list: D036781:Fimbriae Proteins