(A) Purified bacterially produced GST/protein 4.1 fusion proteins in E coli were shown by Coomassie blue staining. (B) Binding of GST/protein 4.1 to pICln in vitro. S³⁵-methionine–labeled pICln (lane 1) was incubated with affinity-purified GST/P80 (lane 2), GST/P30 (lane 3), GST/P10+24 (lane 4), or GST sepharose beads (lane 5). After incubation, the bound protein complexes were analyzed by SDS-PAGE and autoradiography.