Navegando por Palavras-chave "vesicular stomatitis virus"

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    Charged residues are involved in membrane fusion mediated by a hydrophilic peptide located in vesicular stomatitis virus G protein
    (Taylor & Francis Ltd, 2006-09-01) Carneiro, Fabiana A.; Vandenbussche, Guy; Juliano, Maria A.; Juliano, Luiz; Ruysschaert, Jean-Marie; Da Poian, Andrea T.; Universidade Federal do Rio de Janeiro (UFRJ); Univ Libre Bruxelles; Universidade Federal de São Paulo (UNIFESP)
    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 Asp(153) and Glu(158), 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. His(148) 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.
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    A minor beta-structured conformation is the active state of a fusion peptide of vesicular stomatitis virus glycoprotein
    (Wiley-Blackwell, 2008-04-01) Sarzedas, Carolina G.; Lima, Carla S.; Juliano, Maria A. [UNIFESP]; Juliano, Luiz [UNIFESP]; Valente, Ana Paula; Da Poian, Andrea T.; Almeida, Fabio C. L.; Universidade Federal do Rio de Janeiro (UFRJ); Universidade Federal de São Paulo (UNIFESP)
    Entry of enveloped animal viruses into their host cells always depends on a step of 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 at the acidic environment of the endosomal compartment. in a previous work, we identified a specific sequence in the VSV G protein, comprising the residues 145-164, directly involved in membrane interaction and fusion. in the present work we studied the interaction of pep[145-164] with membranes using NMR to solve the structure of the peptide in two membrane-mimetic systems: SDS micelles and liposomes composed of phosphatidylcholme and phosphatidylserine (PC: PS vesicles). the presence of medium-range NOEs showed that the peptide has a tendency to form N- and C-terminal helical segments in the presence of SDS micelles. Analysis of the chemical shift index indicated helix-coil equilibrium for the C-terminal helix under all conditions studied. At pH 7.0, the N-terminal helix also displayed a helix-coil equilibrium when pep[145-164] was free in solution or in the presence of PC: PS. Remarkably, at the fusogenic pH, the region of the N-terminal helix in the presence of SDS or PC: PS presented a third conformational species that was in equilibrium with the helix and random coil. the N-terminal helix content decreases pH and the minor P-structured conformation becomes more prevalent at the fusogenic pH. These data point to a P-conformation as the fusogenic active structure-which is in agreement with the X-ray structure, which shows a P-hairpin for the region corresponding to pep[145-164]. Copyright (c) 2007 European Peptide Society and John Wiley & Sons, Ltd.