Send to

Choose Destination
Nat Struct Mol Biol. 2016 Mar;23(3):192-6. doi: 10.1038/nsmb.3181. Epub 2016 Feb 22.

Structure of the BAM complex and its implications for biogenesis of outer-membrane proteins.

Author information

National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Sciences, Beijing, China.
Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.


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.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Nature Publishing Group
Loading ...
Support Center