Effect of the truncation of coexpression partners (derivatives of mIF) on AMP expression. (A) Schematic representation of the various translationally coupled, two-cistron vectors that expressed truncated mIF and BIIb. (B) SDS-PAGE analysis of the mIF- and BIIb-containing complexes expressed. Lanes 1, 4, 7, and 10 show total cell proteins from E. coli cells that harbored pmIFc-BIIb, pmIFc1-BIIb, pmIFc2-BIIb, or pmIFc3-BIIb, respectively, before IPTG induction. Lanes 2, 5, 8, and 11 show total cell proteins from E. coli cells that contained pmIFc-BIIb, pmIFc1-BIIb, pmIFc2-BIIb, or pmIFc3-BIIb, respectively, after IPTG induction. IPTG (0.5 mM) was added when the OD600 of the E. coli culture reached 0.6. Lanes 3, 6, 9, and 12 show proteins from solubilized inclusion bodies (in 3 M urea, pH 10) isolated from E. coli cells that contained pmIFc-BIIb, pmIFc1-BIIb, pmIFc2-BIIb, or pmIFc3-BIIb, respectively. Lane 13 shows synthetic BIIb, and the arrow indicates recombinant BIIb. Lanes M1 and M2 show molecular size markers, with the actual molecular sizes (in kDa) given by the numbers that flank the gel photograph. (C) Relative amounts of BIIb to mIFn (n = c, c1, or c2) in the mIFn-BIIb complexes isolated from mIFn- and BIIb-expressing E. coli.