Deacylation of the transmembrane domains of Sindbis virus envelope glycoproteins E1 and E2 does not affect low-pH-induced viral membrane fusion activity

The envelope glycoproteins E1 and E2 of Sindbis virus are palmitoylated at cysteine residues within their transmembrane domains (E1 at position 430, a nd E2 at positions 388 and 390), Here, we investigated the in vitro membran e fusion activity of Sindbis virus variants (derived from the Tote 1101 inf ectious clone), in which the E1 C430 and/or E2 C388/390 residues had been s ubstituted for alanines, Both the E1 and E2 mutant viruses, as well as a tr iple mutant virus, fused with liposomes in a strictly low-pH-dependent mann er, the fusion characteristics being indistinguishable from those of the pa rent Tote 1101 virus. These results demonstrate that acylation of the trans membrane domain of Sindbis virus E1 and E2 is not required for expression o f viral membrane fusion activity. (C) 2001 Federation of European Biochemic al Societies. Published by Elsevier Science B.V. All rights reserved.