Immunoblot analysis of LacK′-′MalK chimeras. Cells of strain ES25, harboring the respective plasmids, were grown and further treated as described in the legend to Fig. 3 but were probed with a polyclonal antiserum raised against the purified MalKC1 fragment. Lanes: 1, MalK (pSW7); 2, LacK′-′MalK1 (pGS97-30); 3, LacK′-′MalK2 (pGS97-14); 4, LacK′-′MalK3 (pGS97-24); 5, LacK′-′MalK4 (pGS97-31); 6, control (pSE380).