Fig. 2.

Expression of wild-type and mutant envelope glycoproteins. (A) Metabolically labeled glycoproteins were immunoprecipitated using the G1-specific MAb BF11 and separated on NuPAGE 4–12% Bis–Tris gels. The wild-type (wt) and SKI-1/S1P cleavage-defective (cd) glycoproteins are shown for comparison with the N- and C-terminal heptad-repeat mutants. V326A indicates the glycoprotein in which V326 has been changed to alanine. The two bands labeled GP-C (i.e., the full-length GP-C and the G1–G2 precursor lacking SSP) as well as the heterodisperse smear of G1 are better resolved following deglycosylation using PNGase F (B).