FIG. 2.

Expression of the M₂ protein truncation mutants from cDNAs. HeLa T4 cells were infected with vac-T7 and transfected with plasmids encoding the wt M₂ protein or the truncation mutants. At 5 h posttransfection, the cells were labeled with [³⁵S]methionine (A), [³⁵S]cysteine (B), or [³⁵S]cysteine (C). The cells were lysed, proteins were immunoprecipitated with MAb 14C2, and polypeptides were analyzed by SDS-PAGE on 17.5% acrylamide gels containing 4 M urea. (A and B) Electrophoresis under reducing conditions; (C) electrophoresis under nonreducing conditions. T, tetramers; D, disulfide-linked dimers.