Fig. 2.

Compartmentalized biotinylation assay. Cartoon representations of (A) BirA-catalyzed transfer of biotin to biotin acceptor peptide (BAP)-tagged fusion proteins, and (B) strains producing E.coli BirA in the mother cell (MC) and the forespore (FS). Compartmentalized biotinylation of SpoIIID-BAP (C) and σ^G-BAP (D). Top in C and D are streptavidin-HRP Western blots with lysates prepared at t₃ (SpoIIID-BAP) and t₄ (σ^G-BAP). Lysates were prepared from strains producing different combinations of the indicated BAP-tagged fusion protein and BirA in the mother cell, the forespore, or not at all. C Lower and D Lower show streptavidin Western blots, with the same lysates shown in C Upper and D Upper, comparing levels of biotinyl-biotin carboxyl carrier protein (BCCP).