Structural highlights
Function
BAMA_ECOLI Part of the outer membrane protein assembly complex, which is involved in assembly and insertion of beta-barrel proteins into the outer membrane. Constitutes, with BamD, the core component of the assembly machinery.[1] [2] [3] [4] [5]
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.
Cryo-EM structures reveal multiple stages of bacterial outer membrane protein folding.,Doyle MT, Jimah JR, Dowdy T, Ohlemacher SI, Larion M, Hinshaw JE, Bernstein HD Cell. 2022 Mar 31;185(7):1143-1156.e13. doi: 10.1016/j.cell.2022.02.016. Epub , 2022 Mar 15. PMID:35294859[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Doerrler WT, Raetz CR. Loss of outer membrane proteins without inhibition of lipid export in an Escherichia coli YaeT mutant. J Biol Chem. 2005 Jul 29;280(30):27679-87. Epub 2005 Jun 10. PMID:15951436 doi:http://dx.doi.org/M504796200
- ↑ Werner J, Misra R. YaeT (Omp85) affects the assembly of lipid-dependent and lipid-independent outer membrane proteins of Escherichia coli. Mol Microbiol. 2005 Sep;57(5):1450-9. PMID:16102012 doi:http://dx.doi.org/MMI4775
- ↑ Malinverni JC, Werner J, Kim S, Sklar JG, Kahne D, Misra R, Silhavy TJ. YfiO stabilizes the YaeT complex and is essential for outer membrane protein assembly in Escherichia coli. Mol Microbiol. 2006 Jul;61(1):151-64. PMID:16824102 doi:http://dx.doi.org/10.1111/j.1365-2958.2006.05211.x
- ↑ 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
- ↑ 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
