title: Charged residues are involved in membrane fusion mediated by a hydrophilic peptide located in vesicular stomatitis virus G protein.
abstract: Membrane fusion is an essential step of the internalization process of the enveloped animal viruses. Vesicular stomatitis virus (VSV) infection is mediated by virus spike glycoprotein G, which induces membrane fusion at the acidic environment of the endosomal compartment. In a previous work, we identified a specific sequence in VSV G protein, comprising the residues 145 to 164, directly involved in membrane interaction and fusion. Unlike fusion peptides from other viruses, this sequence is very hydrophilic, containing six charged residues, but it was as efficient as the virus in catalyzing membrane fusion at pH 6.0. Using a carboxyl-modifying agent, dicyclohexylcarbodiimide (DCCD), and several synthetic mutant peptides, we demonstrated that the negative charges of peptide acidic residues, especially Asp153 and Glu158, participate in the formation of a hydrophobic domain at pH 6.0, which is necessary to the peptide-induced membrane fusion. The formation of the hydrophobic region and the membrane fusion itself were dependent on peptide concentration in a higher than linear fashion, suggesting the involvement of peptide oligomerization. His148 was also necessary to hydrophobicity and fusion, suggesting that peptide oligomerization occurs through intermolecular electrostatic interactions between the positively-charged His and a negatively-charged acidic residue of two peptide molecules. Oligomerization of hydrophilic peptides creates a hydrophobic region that is essential for the interaction with the membrane that results in fusion.
authors.affiliation: Instituto de Bioquímica Médica, Programa de Biologia Molecular e Biotecnologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Fabiana A
authors.initials: FA
authors.lastname: Carneiro
authors.forename: Guy
authors.initials: G
authors.lastname: Vandenbussche
authors.forename: Maria A
authors.initials: MA
authors.lastname: Juliano
authors.forename: Luiz
authors.initials: L
authors.lastname: Juliano
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Ruysschaert
authors.forename: Andrea T
authors.initials: AT
authors.lastname: Da Poian
mesh_terms: D000595:Amino Acid Sequence; D001224:Aspartic Acid / Q000737:chemistry; D004024:Dicyclohexylcarbodiimide / Q000737:chemistry; D018698:Glutamic Acid / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008561:Membrane Fusion / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D014721:Vesicular stomatitis Indiana virus / Q000502:physiology; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: C028391:G protein, vesicular stomatitis virus; D008562:Membrane Glycoproteins; D010455:Peptides; D014759:Viral Envelope Proteins; D001224:Aspartic Acid; D018698:Glutamic Acid; D004024:Dicyclohexylcarbodiimide