Probing the interaction between vesicular stomatitis virus and phosphatidylserine.
The entry of enveloped animal viruses into their host cells always depends on membrane fusion triggered by conformational changes in viral envelope glycoproteins. Vesicular stomatitis virus (VSV) infection is mediated by virus spike glycoprotein G, which induces membrane fusion between the viral envelope and the endosomal membrane at the acidic environment of this compartment. In this work, we evaluated VSV interactions with membranes of different phospholipid compositions, at neutral and acidic pH, using atomic force microscopy (AFM) operating in the force spectroscopy mode, isothermal calorimetry (ITC) and molecular dynamics simulation. We found that the binding forces differed dramatically depending on the membrane phospholipid composition, revealing a high specificity of G protein binding to membranes containing phosphatidylserine (PS). In a previous work, we showed that the sequence corresponding amino acid 164 of VSV G protein was as efficient as the virus in catalyzing membrane fusion at pH 6.0. Here, we used this sequence to explore VSV-PS interaction using ITC. We found that peptide binding to membranes was exothermic, suggesting the participation of electrostatic interactions. Peptide-membrane interaction at pH 7.5 was shown to be specific to PS and dependent on the presence of His residues in the fusion peptide. The application of the simplified continuum Gouy-Chapman theory to our system predicted a pH of 5.0 at membrane surface, suggesting that the His residues should be protonated when located close to the membrane. Molecular dynamics simulations suggested that the peptide interacts with the lipid bilayer through its N-terminal residues, especially Val(145) and His(148).
Carneiro
Fabiana A
FA
Instituto de Bioquìmica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-590, Brazil.
Lapido-Loureiro
Pedro A
PA
Cordo
Sandra M
SM
Stauffer
Fausto
F
Weissmüller
Gilberto
G
Bianconi
M Lucia
ML
Juliano
Maria A
MA
Juliano
Luiz
L
Bisch
Paulo M
PM
Da Poian
Andrea T
AT
Poian
Andrea T Da
AT
D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D002151:Calorimetry; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003198:Computer Simulation; D006639:Histidine / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008081:Liposomes / Q000737:chemistry; D008562:Membrane Glycoproteins / Q000378:metabolism; D018625:Microscopy, Atomic Force; D010718:Phosphatidylserines / Q000378:metabolism*; D011485:Protein Binding; D055672:Static Electricity; D013816:Thermodynamics; D014633:Valine / Q000737:chemistry; D014721:Vesicular stomatitis Indiana virus / Q000378:metabolism*; D014759:Viral Envelope Proteins / Q000378:metabolism; D014760:Viral Fusion Proteins / Q000378:metabolism
D000596:Amino Acids; C028391:G protein, vesicular stomatitis virus; D008081:Liposomes; D008562:Membrane Glycoproteins; D010718:Phosphatidylserines; D014759:Viral Envelope Proteins; D014760:Viral Fusion Proteins; D006639:Histidine; D014633:Valine