Structural highlights
Function
BAMB_ECOLI Part of the outer membrane protein assembly complex, which is involved in assembly and insertion of beta-barrel proteins into the outer membrane. Nonessential member of the complex, which may orient the flexible periplasmic domain of BamA for interaction with other Bam components, chaperones and nascent outer membrane proteins.[1] [2] [3] [4]
Publication Abstract from PubMed
The beta-barrel assembly machinery (BAM) is a approximately 203 kDa complex of five proteins (BamA-E), which is essential for viability in E. coli. BAM promotes the folding and insertion of beta-barrel proteins into the outer membrane via a poorly understood mechanism. Several current models suggest that BAM functions through a 'lateral gating' motion of the beta-barrel of BamA. Here we present a cryo-EM structure of the BamABCDE complex, at 4.9 A resolution. The structure is in a laterally open conformation showing that gating is independent of BamB binding. We describe conformational changes throughout the complex and interactions between BamA, B, D and E, and the detergent micelle that suggest communication between BAM and the lipid bilayer. Finally, using an enhanced reconstitution protocol and functional assays, we show that for the outer membrane protein OmpT, efficient folding in vitro requires lateral gating in BAM.
Lateral opening in the intact beta-barrel assembly machinery captured by cryo-EM.,Iadanza MG, Higgins AJ, Schiffrin B, Calabrese AN, Brockwell DJ, Ashcroft AE, Radford SE, Ranson NA Nat Commun. 2016 Sep 30;7:12865. doi: 10.1038/ncomms12865. PMID:27686148[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Hagan CL, Kim S, Kahne D. Reconstitution of outer membrane protein assembly from purified components. Science. 2010 May 14;328(5980):890-2. doi: 10.1126/science.1188919. Epub 2010 Apr, 8. PMID:20378773 doi:10.1126/science.1188919
- ↑ Hagan CL, Kahne D. The reconstituted Escherichia coli Bam complex catalyzes multiple rounds of beta-barrel assembly. Biochemistry. 2011 Sep 6;50(35):7444-6. doi: 10.1021/bi2010784. Epub 2011 Aug 11. PMID:21823654 doi:10.1021/bi2010784
- ↑ Albrecht R, Zeth K. Structural basis of outer membrane protein biogenesis in bacteria. J Biol Chem. 2011 Aug 5;286(31):27792-803. Epub 2011 May 17. PMID:21586578 doi:10.1074/jbc.M111.238931
- ↑ Noinaj N, Fairman JW, Buchanan SK. The Crystal Structure of BamB Suggests Interactions with BamA and Its Role within the BAM Complex. J Mol Biol. 2011 Jan 26. PMID:21277859 doi:10.1016/j.jmb.2011.01.042
- ↑ Iadanza MG, Higgins AJ, Schiffrin B, Calabrese AN, Brockwell DJ, Ashcroft AE, Radford SE, Ranson NA. Lateral opening in the intact beta-barrel assembly machinery captured by cryo-EM. Nat Commun. 2016 Sep 30;7:12865. doi: 10.1038/ncomms12865. PMID:27686148 doi:http://dx.doi.org/10.1038/ncomms12865
