Abstact

In Escherichia coli, the BAM complex is essential for the assembly and insertion of outer membrane proteins (OMPs). The BAM complex is comprised of an integral β-barrel outer membrane protein BamA and four accessory lipoproteins BamB, BamC, BamD and BamE. Here, the crystal structure of BamB is reported. The crystal of BamB diffracted to 2.0 Å with one monomer in the asymmetric unit and the structure is composed of eight-bladed β-propeller motifs. Pull-down and Western blotting assays indicate that BamB interacts directly with the POTRA 1-3 domain of BamA and the C-terminal region of the POTRA 1-3 domain plays an important role in the interaction, while the POTRA 1-2 domain is not required for the interaction.