Related Experiment Video
Updated: Jun 14, 2025
11:33
Monitoring the Assembly of a Secreted Bacterial Virulence Factor Using Site-specific Crosslinking
Published on: December 17, 2013
6.2K
Outer membrane protein assembly mediated by BAM-SurA complexes.
Katherine L Fenn1, Jim E Horne1,2, Joel A Crossley1
1Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
Nature Communications
|September 1, 2024
Summary
The periplasmic chaperone SurA delivers unfolded outer membrane proteins (OMPs) to the β-barrel assembly machinery (BAM) in Gram-negative bacteria. This study reveals how SurA interacts with BAM to facilitate OMP insertion and outer membrane biogenesis.
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- The Gram-negative bacterial outer membrane is crucial for protection.
- Outer membrane protein (OMP) insertion relies on the β-barrel assembly machinery (BAM).
- The periplasmic chaperone SurA delivers unfolded OMPs to BAM, but the mechanism is unclear.
Purpose of the Study:
- To elucidate the mechanism of SurA-mediated OMP delivery to BAM.
- To understand the structural basis of SurA-BAM interaction for OMP biogenesis.
Main Methods:
- Disulphide bond engineering to trap SurA-BAM complexes.
- Cryo-electron microscopy (cryo-EM) to solve complex structures.
- AlphaFold2 modeling to guide experiments.
Main Results:
- SurA binds BAM at the POTRA-1 domain, inducing conformational changes.
- OMP transfer to the BAM lateral gate is facilitated by SurA-BAM interaction.
- Disruption of SurA-BAM interaction causes outer membrane assembly defects.
Conclusions:
- SurA plays a critical role in outer membrane biogenesis by mediating OMP transfer to BAM.
- The SurA-BAM interaction is essential for bacterial outer membrane integrity.
- Structural insights into SurA-BAM complex formation advance understanding of OMP insertion.
More Related Videos
Related Concept Videos
02:41Protein Complex Assembly
10.6K
Proteins can form homomeric complexes with another unit of the same protein or heteromeric complexes with different types. Most protein complexes self-assemble spontaneously via ordered pathways, while some proteins need assembly factors that guide their proper assembly. Despite the crowded intracellular environment, proteins usually interact with their correct partners and form functional complexes.
Many viruses self-assemble into a fully functional unit using the infected host cell to...
Many viruses self-assemble into a fully functional unit using the infected host cell to...
10.6K
01:12Porin Insertion in the Outer Mitochondrial Membrane
2.9K
Porins are beta-barrel proteins translocated to the mitochondrial outer membrane through the TOM complex into the intermembrane space. Porin precursors bind TIM chaperones within the intermembrane space and are guided to the Sorting and Assembly Machinery complex or SAM complex on the outer mitochondrial membrane.
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
2.9K
01:33Coat Assembly and GTPases
3.5K
Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
3.5K
01:21Structure of Porins
2.9K
Mitochondria, chloroplasts, and gram-negative bacteria have transmembrane, beta-barrel proteins called porins to mediate the free diffusion of ions and metabolites across the membrane. Mitochondrial porin precursors contain conserved amino acid sequences called beta signals at their C-terminal. Beta signals have a motif of PoXGXXHyXHy (Po-Polar, X-Any amino acid, G-Glycine, Hy-LargeHydrophobic), which are crucial for precursor recognition to initiate precursor assembly. Beta-barrel...
2.9K
01:30Assembly of Signaling Complexes
5.7K
Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
5.7K
01:38Intralumenal Vesicles and Multivesicular Bodies
3.4K
Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...
3.4K