Figure 5. Affinity purification of the BldM-WhiI complex.

N-terminally His₆-tagged BldM and either (A) untagged WhiI, or (B) N-terminally S_II-tagged WhiI, were co-expressed from the pETDuet-1 vector. In both cases, co-expression of BldM solubilized WhiI, which formed inclusion bodies when expressed alone. The His₆-BldMWhiI complex in (A) was purified over a HisTrap Ni affinity column, and the His₆-BldM-S_II-whiI complex in (B) was purified over consecutive HisTrap Ni and StrepTrap HP affinity columns.