FhuA interactions in a detergent-free nanodisc environment
| Autor: | Franck Duong, Hai-Tuong Le, James W. Coulton, Allan Mills |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
β-Barrel proteins
Recombinant Fusion Proteins Lipid Bilayers Biophysics Colicins Gene Expression Biochemistry Protein Structure Secondary Siderophore Channels Escherichia coli Binding site Nanodisc Binding Sites Chemistry Escherichia coli Proteins Molecular Mimicry Membrane Nanodiscs Isothermal titration calorimetry Cell Biology biochemical phenomena metabolism and nutrition Ligand (biochemistry) Binding constant Transporters Kinetics Membrane protein Colicin bacteria Thermodynamics Ferrichrome Bacterial Outer Membrane Proteins Protein Binding |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 1838(1):364-371 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/j.bbamem.2013.09.022 |
| Popis: | TonB-dependent membrane receptors from bacteria have been analyzed in detergent-containing solution, an environment that may influence the role of ligand in inducing downstream interactions. We report reconstitution of FhuA into a membrane mimetic: nanodiscs. In contrast to previous results in detergent, we show that binding of TonB to FhuA in nanodiscs depends strongly on ferricrocin. The stoichiometry of interaction is 1:1 and the binding constant KD is ~200nM; an equilibrium affinity that is ten-fold lower than reported in detergent. FhuA in nanodiscs also forms a high-affinity binding site for colicin M (KD ~3.5nM), while ferricrocin renders FhuA refractory to colicin binding. Together, these results demonstrate the importance of the ligand in regulating receptor interactions and the advantages of nanodiscs to study β-barrel membrane proteins in a membrane-like environment. |
| Databáze: | OpenAIRE |
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