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
beta-barrel outer membrane proteins (beta-OMPs) play critical roles in nutrition acquisition, protein import/export, and other fundamental biological processes. The assembly of beta-OMPs in Gram-negative bacteria is mediated by the beta-barrel assembly machinery (BAM) complex, yet its precise mechanism remains elusive. Here, we report two structures of the BAM complex in detergents and in nanodisks, and two crystal structures of the BAM complex with bound substrates. Structural analysis indicates that the membrane compositions surrounding the BAM complex could modulate its overall conformations, indicating low energy barriers between different conformational states and a highly dynamic nature of the BAM complex. Importantly, structures of the BAM complex with bound substrates and the related functional analysis show that the first beta-strand of the BamA beta-barrel (beta1(BamA) ) in the BAM complex is associated with the last but not the first beta-strand of a beta-OMP substrate via antiparallel beta-strand interactions. These observations are consistent with the beta-signal hypothesis during beta-OMP biogenesis, and suggest that the beta1(BamA) strand in the BAM complex may interact with the last beta-strand of an incoming beta-OMP substrate upon their release from the chaperone-bound state.
Structures of the beta-barrel assembly machine recognizing outer membrane protein substrates.,Xiao L, Han L, Li B, Zhang M, Zhou H, Luo Q, Zhang X, Huang Y FASEB J. 2021 Jan;35(1):e21207. doi: 10.1096/fj.202001443RR. PMID:33368572[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
- ↑ Xiao L, Han L, Li B, Zhang M, Zhou H, Luo Q, Zhang X, Huang Y. Structures of the β-barrel assembly machine recognizing outer membrane protein substrates. FASEB J. 2021 Jan;35(1):e21207. PMID:33368572 doi:10.1096/fj.202001443RR
