Structure of the BAM complex and its implications for biogenesis of outer-membrane proteins
Han, L., Zheng, J., Wang, Y., Yang, X., Liu, Y., Sun, C., Cao, B., Zhou, H., Ni, D., Lou, J., Zhao, Y., Huang, Y.(2016) Nat Struct Mol Biol 23: 192-196
- PubMed: 26900875 
- DOI: https://doi.org/10.1038/nsmb.3181
- Primary Citation of Related Structures:  
5AYW - PubMed Abstract: 
In Gram-negative bacteria, the assembly of β-barrel outer-membrane proteins (OMPs) requires the β-barrel-assembly machinery (BAM) complex. We determined the crystal structure of the 200-kDa BAM complex from Escherichia coli at 3.55-Å resolution. The structure revealed that the BAM complex assembles into a hat-like shape, in which the BamA β-barrel domain forms the hat's crown embedded in the outer membrane, and its five polypeptide transport-associated (POTRA) domains interact with the four lipoproteins BamB, BamC, BamD and BamE, thus forming the hat's brim in the periplasm. The assembly of the BAM complex creates a ring-like apparatus beneath the BamA β-barrel in the periplasm and a potential substrate-exit pore located at the outer membrane-periplasm interface. The complex structure suggests that the chaperone-bound OMP substrates may feed into the chamber of the ring-like apparatus and insert into the outer membrane via the potential substrate-exit pore in an energy-independent manner.
Organizational Affiliation: 
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.