Immunodetection of epitope-tagged proteins from
Salmonella prophages. Whole-cell bacterial lysates were
subjected to electrophoretic separation in a 12% polyacrylamide-SDS
gel. Proteins were transferred onto poly(vinylidene difluoride)
membrane and probed with anti-FLAG M2 mAb (Sigma). (A)
Bacteria grown in LB medium: 1, strain MA7172
(sodCI-30∷3xFLAG KnR); 2,
strain MA7180 (gtgE-34∷3xFLAG KnR); 3,
strain MA7191 (sodCIII-35∷3xFLAG KnR);
and 4, strain MA7192 (gogC-36∷3xFLAG
KnR). Expected molecular masses for the 3xFLAG fusion
proteins are: SodCI and SodCIII, 19 kDa; GtgE, 29 kDa; and GogC, 22
kDa. (B) Bacteria grown under conditions eliciting
SsrB-mediated regulation. Lanes 1–4: strain MA7184
(gogB-33∷3xFLAG KnR
ssrB∷ Cm/pBAD ssrB+)
grown in LB medium (lane 1), in LB medium supplemented with arabinose
(lane 2), in M9-glucose medium (lane 3), and in M9-arabinose medium
(lane 4). Lanes 5–8: strain MA7185 (gtgB-37∷3xFLAG
KnR ssrB∷Cm/pBAD
ssrB+) grown in M9-glucose medium (lane 5),
in M9-arabinose medium (lane 6), in LB medium (lane 7), and in LB
medium supplemented with arabinose (lane 8). Expected molecular masses
for the 3xFLAG fusion proteins are: GtgB, 38 kDa and GogB, 57 kDa.
Positions and molecular masses (kDa) of protein standards are indicated
on the left.