The protein-protein interactions involved in the periplasmic components of the β-barrel assembly machinery (BAM) complex of Escherichia coli

The β-barrel assembly machinery (BAM) complex plays the essential role of folding and inserting outer membrane proteins (OMPs) into the outer membrane of Gram-negative bacteria. In Escherichia coli, the BAM complex is comprised of five proteins: BamA, BamB, BamC, BamD, and BamE. This thesis project investigates the interactions between the periplasmic components of the BAM complex by analyzing complex formation using gel-filtration chromatography. Results from the interaction studies have identified the unstructured N-termini of BamC and BamE as requirements for BamCDE subcomplex formation. Furthermore, BamAPOTRA was shown to form stable BamAPOTRA-BamB and BamAPOTRA-BamD-BamE complexes, but was unable to form the latter complex in the presence of BamC. Together these results provide a model for how the proteins assemble and suggest that the complex is dynamic. By understanding how the BAM components come together brings us one step closer to determining their individual roles and how the BAM complex may function overall.