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
Transmembrane beta barrel proteins are folded into the outer membrane (OM) of Gram-negative bacteria by the beta barrel assembly machinery (BAM) via a poorly understood process that occurs without known external energy sources. Here, we used single-particle cryo-EM to visualize the folding dynamics of a model beta barrel protein (EspP) by BAM. We found that BAM binds the highly conserved "beta signal" motif of EspP to correctly orient beta strands in the OM during folding. We also found that the folding of EspP proceeds via "hybrid-barrel" intermediates in which membrane integrated beta sheets are attached to the essential BAM subunit, BamA. The structures show an unprecedented deflection of the membrane surrounding the EspP intermediates and suggest that beta sheets progressively fold toward BamA to form a beta barrel. Along with in vivo experiments that tracked beta barrel folding while the OM tension was modified, our results support a model in which BAM harnesses OM elasticity to accelerate beta barrel folding.
, PMID:35294859[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
- ↑ Doyle MT, Jimah JR, Dowdy T, Ohlemacher SI, Larion M, Hinshaw JE, Bernstein HD. Cryo-EM structures reveal multiple stages of bacterial outer membrane protein folding. Cell. 2022 Mar 31;185(7):1143-1156.e13. PMID:35294859 doi:10.1016/j.cell.2022.02.016
