title: Membrane fusion activity of vesicular stomatitis virus glycoprotein G is induced by low pH but not by heat or denaturant.
abstract: The fusogenic envelope glycoprotein G of the rhabdovirus vesicular stomatitis virus (VSV) induces membrane fusion at acidic pH. At acidic pH the G protein undergoes a major structural reorganization leading to the fusogenic conformation. However, unlike other viral fusion proteins, the low-pH-induced conformational change of VSV G is completely reversible. As well, the presence of an alpha-helical coiled-coil motif required for fusion by a number of viral and cellular fusion proteins was not predicted in VSV G protein by using a number of algorithms. Results of pH dependence of the thermal stability of G protein as determined by intrinsic Trp fluorescence and circular dichroism (CD) spectroscopy show that the G protein is equally stable at neutral or acidic pH. Destabilization of G structure at neutral pH with either heat or urea did not induce membrane fusion or conformational change(s) leading to membrane fusion. Taken together, these data suggest that the mechanism of VSV G-induced fusion is distinct from the fusion mechanism of fusion proteins that involve a coiled-coil motif.
authors.affiliation: Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yao
authors.forename: Kakoli
authors.initials: K
authors.lastname: Ghosh
authors.forename: Raquel F
authors.initials: RF
authors.lastname: Epand
authors.forename: Richard M
authors.initials: RM
authors.lastname: Epand
authors.forename: Hara P
authors.initials: HP
authors.lastname: Ghosh
mesh_terms: D000818:Animals; D002460:Cell Line; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008561:Membrane Fusion / Q000187:drug effects; D008562:Membrane Glycoproteins / Q000378:metabolism*; D013997:Time Factors; D014508:Urea / Q000494:pharmacology; D014721:Vesicular stomatitis Indiana virus / Q000502:physiology*; D014759:Viral Envelope Proteins / Q000378:metabolism*; D014779:Virus Replication
chemical_list: C028391:G protein, vesicular stomatitis virus; D008562:Membrane Glycoproteins; D014759:Viral Envelope Proteins; D014508:Urea