FIG. 3.
The C-terminal domain of the S protein is accessible to proteases in inverted membrane vesicles. E. coli MC4100(pBS112) cells were infected with λCE6 and labelled with [35S]methionine at 25 min after infection. Spheroplasts and IMV, treated with proteinase K, with or without detergent, for various times as indicated. Each sample was subjected to immunoprecipitation with anti-S antibody (9), and the immunoprecipitate was analyzed by SDS-polyacrylamide gel electrophoresis and autoradiography. Lanes: 1, in vitro translation products of S+ mRNA, as described previously (9); 2 to 5, spheroplast samples; 6 to 11, IMV samples.