FIG. 5.

Effect of amplification of the ileX, argU, and leuW genes on production of the botulinum C3 protein (A), the iota toxin Ia protein (B), and the light chain of tetanus toxin (C) in BL21(λDE3) cells. The expression of each protein was evaluated in the absence or in the presence of amplified ileX, argU, or leuW genes, as follows: lane 1, no amplification (pACYC184); lane 2, pACYC-Arg34; lane 3, pACYC-Ile7; lane 4, pACYC-L10; lane 5, pACYC-IleArg10; lane 6, pACYC-RL5; and lane 7, pACYC-IRL10. Cells were induced with IPTG and processed for SDS-PAGE as described in the legend to Fig. 2. The arrows indicate the locations of proteins C3 and Ia and the light chain of tetanus toxin (TeNT-L). The molecular weight markers used (lane M) were the molecular weight markers described in the legend to Fig. 3.