Membrane association induces a conformational change in the Ebola virus matrix protein.
The matrix protein VP40 from Ebola virus is targeted to the plasma membrane, where it is thought to induce assembly and budding of virions through its association with the lipid bilayer. Ebola virus VP40 is expressed as a monomeric molecule in solution, consisting of two loosely associated domains. Here we show that a C-terminal truncation of seven residues destabilizes the monomeric closed conformation and induces spontaneous hexamerization in solution, as indicated by chemical cross-linking and electron microscopy. Three-dimensional reconstruction of electron microscopy images shows ring-like structures consisting of the N-terminal domain along with evidence for flexibly attached C-terminal domains. In vitro destabilization of the monomer by urea treatment results in similar hexameric molecules in solution. In addition, we demonstrate that membrane association of wild-type VP40 also induces the conformational switch from monomeric to hexameric molecules that may form the building blocks for initiation of virus assembly and budding. Such a conformational change induced by bilayer targeting may be a common feature of many viral matrix proteins and its potential inhibition may result in new anti-viral therapies.
Scianimanico
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S
European Molecular Biology Laboratory (EMBL) Grenoble Outstation, 6 rue Jules Horowitz, 38000 Grenoble, France.
Schoehn
G
G
Timmins
J
J
Ruigrok
R H
RH
Klenk
H D
HD
Weissenhorn
W
W
D002462:Cell Membrane / Q000821:virology; D018360:Crystallography, X-Ray; D029043:Ebolavirus / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D008081:Liposomes; D008854:Microscopy, Electron; D008958:Models, Molecular; D009698:Nucleoproteins / Q000737:chemistry* / Q000502:physiology* / Q000648:ultrastructure; D010446:Peptide Fragments / Q000737:chemistry; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000648:ultrastructure; D017384:Sequence Deletion; D012984:Software; D012996:Solutions; D014508:Urea; D014758:Viral Core Proteins / Q000737:chemistry* / Q000502:physiology* / Q000648:ultrastructure; D014771:Virion / Q000502:physiology
D008081:Liposomes; D009698:Nucleoproteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D012996:Solutions; D014758:Viral Core Proteins; C084819:nucleoprotein VP40, Ebola virus; D014508:Urea