7ncs

From Proteopedia

Lateral-open conformation of the lid-locked BAM complex (BamA E435C S665C, BamBDCE) bound by a bactericidal Fab fragment

Structural highlights

7ncs is a 7 chain structure with sequence from Escherichia coli K-12 and Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 7.1Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

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

The folding of beta-barrel outer membrane proteins (OMPs) in Gram-negative bacteria is catalysed by the beta-barrel assembly machinery (BAM). How lateral opening in the beta-barrel of the major subunit BamA assists in OMP folding, and the contribution of membrane disruption to BAM catalysis remain unresolved. Here, we use an anti-BamA monoclonal antibody fragment (Fab1) and two disulphide-crosslinked BAM variants (lid-locked (LL), and POTRA-5-locked (P5L)) to dissect these roles. Despite being lethal in vivo, we show that all complexes catalyse folding in vitro, albeit less efficiently than wild-type BAM. CryoEM reveals that while Fab1 and BAM-P5L trap an open-barrel state, BAM-LL contains a mixture of closed and contorted, partially-open structures. Finally, all three complexes globally destabilise the lipid bilayer, while BamA does not, revealing that the BAM lipoproteins are required for this function. Together the results provide insights into the role of BAM structure and lipid dynamics in OMP folding.

The role of membrane destabilisation and protein dynamics in BAM catalysed OMP folding.,White P, Haysom SF, Iadanza MG, Higgins AJ, Machin JM, Whitehouse JM, Horne JE, Schiffrin B, Carpenter-Platt C, Calabrese AN, Storek KM, Rutherford ST, Brockwell DJ, Ranson NA, Radford SE Nat Commun. 2021 Jul 7;12(1):4174. doi: 10.1038/s41467-021-24432-x. PMID:34234105^[6]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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Citations

reviews cite this structure

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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
↑ White P, Haysom SF, Iadanza MG, Higgins AJ, Machin JM, Whitehouse JM, Horne JE, Schiffrin B, Carpenter-Platt C, Calabrese AN, Storek KM, Rutherford ST, Brockwell DJ, Ranson NA, Radford SE. The role of membrane destabilisation and protein dynamics in BAM catalysed OMP folding. Nat Commun. 2021 Jul 7;12(1):4174. PMID:34234105 doi:10.1038/s41467-021-24432-x