FIG. 1.

OmpF trimer assays. Cells expressing various OmpF proteins were grown to mid-log phase at 42^oC in glycerol minimal medium, labeled for 20 s with [³⁵S]methionine-cysteine, and chased with an excess of nonradioactive methionine. Chase samples were removed after 1, 3, 10, and 30 min. Proteins were extracted, and OmpF was immunoprecipitated using trimer-specific antibodies. Immunoprecipitates were heated at 60°C for 15 min prior to analysis by SDS-PAGE. The gel was dried and subjected to autoradiography at −70°C. Positions of OmpF trimers (T) and denatured monomers (M) are shown. Relevant alterations in various OmpF proteins are shown below the gel. The loading of 1- and 3-min chase samples carrying OmpF with a T216I alteration was inadvertently reversed.