ArticleEuropean biophysics journal : EBJ2013
Folding and stability of outer membrane protein A (OmpA) from Escherichia coli in an amphipathic polymer, amphipol A8-35.
Article in European biophysics journal : EBJ, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 36 papers.
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36 citing papers in PubMed, 73 citations in OpenAlex.
- Sited-Directed Fluorescence Spectroscopy for Studies on the Folding and Insertion of Proteins in Lipid Bilayers and Model Membranes.Methods in molecular biology (Clifton, N.J.) · 2026Article
- Advances in Crystallography and Cryo-Electron Microscopy for the Study of Membrane Proteins.Advances in experimental medicine and biology · 2026Review
- Effect of the Bacterial Chaperones SecB and Trigger Factor (TF) on the Folding Dynamics and In Vitro Translocation of Cytoplasmic and Secretory Model Proteins.International journal of molecular sciences · 2025Article
- Surface Engineering ofCurrent issues in molecular biology · 2024Article
- Spin-Label Electron Paramagnetic Resonance Spectroscopy Reveals Effects of Wastewater Filter Membrane Coated with Titanium Dioxide Nanoparticles on Bovine Serum Albumin.Molecules (Basel, Switzerland) · 2023Article
- The Thermodynamic Stability of Membrane Proteins in Micelles and Lipid Bilayers Investigated with the Ferrichrom Receptor FhuA.The Journal of membrane biology · 2022Article
- Full-length G glycoprotein directly extracted from rabies virus with detergent and then stabilized by amphipols in liquid and freeze-dried forms.Biotechnology and bioengineering · 2021Article
- An engineered genetic circuit for lactose intolerance alleviation.BMC biology · 2021Article
- Role of the lipid bilayer in outer membrane protein folding in Gram-negative bacteria.The Journal of biological chemistry · 2020Review
- Determining the amphipol distribution within membrane-protein fibre samples using small-angle neutron scattering.Acta crystallographica. Section D, Structural biology · 2018Article
- A targeted boost-and-sort immunization strategy using Escherichia coli BamA identifies rare growth inhibitory antibodies.Scientific reports · 2018Article
- Detergent Desorption of Membrane Proteins Exhibits Two Kinetic Phases.The journal of physical chemistry letters · 2018Article
- Outer membrane protein folding from an energy landscape perspective.BMC biology · 2017Review
- Transmembrane β-barrels: Evolution, folding and energetics.Biochimica et biophysica acta. Biomembranes · 2017Review
- Kinetic stability of membrane proteins.Biophysical reviews · 2017Review
- Energetics of side-chain partitioning of β-signal residues in unassisted folding of a transmembrane β-barrel protein.The Journal of biological chemistry · 2017Article
- FPOP-LC-MS/MS Suggests Differences in Interaction Sites of Amphipols and Detergents with Outer Membrane Proteins.Journal of the American Society for Mass Spectrometry · 2017Article
- Control of human VDAC-2 scaffold dynamics by interfacial tryptophans is position specific.Biochimica et biophysica acta · 2016Article
- N-helix and Cysteines Inter-regulate Human Mitochondrial VDAC-2 Function and Biochemistry.The Journal of biological chemistry · 2015Article
- Systematic analysis of the use of amphipathic polymers for studies of outer membrane proteins using mass spectrometry.International journal of mass spectrometry · 2015Article
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Authors and funding
3 authors at 3 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Amphipols are a class of amphipathic polymers designed to maintain membrane proteins in aqueous solutions in the absence of detergents. Denatured β-barrel membrane proteins, like outer membrane proteins OmpA from Escherichia coli and FomA from Fusobacterium nucleatum, can be folded by dilution of the denaturant urea in the presence of amphipol A8-35. Here, the folding kinetics and stability of OmpA in A8-35 have been investigated. Folding is well described by two parallel first-order processes, whose half-times, ~5 and ~70 min, respectively, are independent of A8-35 concentration. The faster process contributed ~55-64 % to OmpA folding. Folding into A8-35 was faster than into dioleoylphosphatidylcholine bilayers and complete at ratios as low as ~0.17 g/g A8-35/OmpA, corresponding to ~1-2 A8-35 molecules per OmpA. Activation energies were determined from the temperature dependence of folding kinetics, monitored both by electrophoresis, which reports on the formation of stable OmpA tertiary structure, and by fluorescence spectroscopy, which reflects changes in the environment of tryptophan side chains. The two methods yielded consistent estimates, namely ~5-9 kJ/mol for the fast process and ~29-37 kJ/mol for the slow one, which is lower than is observed for OmpA folding into dioleoylphosphatidylcholine bilayers. Folding and unfolding titrations with urea demonstrated that OmpA folding into A8-35 is reversible and that amphipol-refolded OmpA is thermodynamically stable at room temperature. Comparison of activation energies for folding and unfolding in A8-35 versus detergent indicates that stabilization of A8-35-trapped OmpA against denaturation by urea is a kinetic, not a thermodynamic phenomenon.
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