title: Low-pH conformational changes of rabies virus glycoprotein and their role in membrane fusion.
abstract: Fusion of rabies virus with membranes occurs at acidic pH and is mediated by the viral spike glycoprotein (G). In this paper, we provide the basis for a description of structural transitions associated with exposure to low pH and of their role in membrane fusion. First, we have extended previous studies of fusion kinetics and we have shown that low-pH inhibition of fusion is detectable at 0.5 pH units higher than fusion. Second, low-pH-induced conformational changes were analyzed by using electron microscopy and monoclonal antibody binding assays. The existence of a pH-dependent equilibrium between the native and a low-pH inactive conformation was demonstrated. Third, besides these two conformations, we, using the fluorescent probe ANS (8-anilino-1-naphthalenesulfonic acid), provide evidence for the existence of a transient third state which appears to be more hydrophobic than the native state. Our results suggest that this transient state is responsible for viral aggregation at low pH and could play a role in the first steps of the fusion mechanism.
authors.affiliation: Laboratoire de Génétique des Virus, Centre National de la Recherche Scientifique, Gif sur Yvette, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Gaudin
authors.forename: R W
authors.initials: RW
authors.lastname: Ruigrok
authors.forename: M
authors.initials: M
authors.lastname: Knossow
authors.forename: A
authors.initials: A
authors.lastname: Flamand
mesh_terms: D000817:Anilino Naphthalenesulfonates; D000911:Antibodies, Monoclonal; D000956:Antigens, Viral / Q000737:chemistry* / Q000276:immunology; D006023:Glycoproteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008081:Liposomes; D008561:Membrane Fusion; D008956:Models, Chemical; D016624:Negative Staining; D011487:Protein Conformation; D011820:Rabies virus / Q000737:chemistry* / Q000276:immunology / Q000648:ultrastructure; D013050:Spectrometry, Fluorescence; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D014760:Viral Fusion Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D014771:Virion / Q000737:chemistry / Q000276:immunology / Q000648:ultrastructure
chemical_list: D000817:Anilino Naphthalenesulfonates; D000911:Antibodies, Monoclonal; D000956:Antigens, Viral; D006023:Glycoproteins; D008081:Liposomes; D014759:Viral Envelope Proteins; D014760:Viral Fusion Proteins; C064951:glycoprotein G, Rabies virus; C027132:1-anilino-8-naphthalenesulfonate