Altered G-protein glycosylation in vesicular stomatitis virus-infected glucose-deprived baby hamster kidney cells.

The glycosylation of the G-protein was analyzed in vesicular stomatitis virus-infected baby hamster kidney cells incubated in the absence of glucose. The results indicate that the G-protein in glucose-starved cells is initially glycosylated from a lipid donor with a glucosylated oligosaccharide which is resistant to endo-beta-N-acetylglucosaminidase H and partially susceptible to alpha-mannosidase. With longer times, the protein-bound carbohydrate chain becomes much more sensitive to alpha-mannosidase while remaining endo-beta-N-acetylglucosaminidase H-resistant. Purified virions from glucose-starved baby hamster kidney cells, labeled with [35S]methionine and isolated on a sucrose gradient, contain altered forms of the G-protein, whereas the other viral proteins remain unchanged. These altered forms could also be radiolabeled with [3H]mannose, and upon analysis of labeled glycopeptides by chromatography on concanavalin A-Sepharose and Bio-Gel P-6, it was apparent that modification of the oligosaccharide portion of the G-protein occurs in baby hamster kidney cells, leading to aberrant mature carbohydrate chains.