Distance Measurement on an Endogenous Membrane Transporter in E. coli Cells and Native Membranes Using EPR Spectroscopy |
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| Authors: | Dr. Benesh Joseph Arthur Sikora Prof. Dr. Enrica Bordignon Prof. Dr. Gunnar Jeschke Prof. Dr. David S. Cafiso Prof. Dr. Thomas F. Prisner |
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| Affiliation: | 1. Institut für physikalische und theoretische Chemie und Biomolekulares Magnetresonanz Zentrum, Universit?t Frankfurt, Max‐von‐Laue‐Strasse 7, 60438 Frankfurt am Main (Germany) http://www.prisner.de;2. Department of Chemistry, University of Virginia, McCormick Road, Charlottesville VA22904‐4319 (USA);3. Department of Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin (Germany);4. Laboratory for Physical Chemistry, ETH Zurich, Vladimir‐Prelog‐Weg 2, 8093 Zürich (Switzerland) |
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| Abstract: | Membrane proteins may be influenced by the environment, and they may be unstable in detergents or fail to crystallize. As a result, approaches to characterize structures in a native environment are highly desirable. Here, we report a novel general strategy for precise distance measurements on outer membrane proteins in whole Escherichia coli cells and isolated outer membranes. The cobalamin transporter BtuB was overexpressed and spin‐labeled in whole cells and outer membranes and interspin distances were measured to a spin‐labeled cobalamin using pulse EPR spectroscopy. A comparative analysis of the data reveals a similar interspin distance between whole cells, outer membranes, and synthetic vesicles. This approach provides an elegant way to study conformational changes or protein–protein/ligand interactions at surface‐exposed sites of membrane protein complexes in whole cells and native membranes, and provides a method to validate outer membrane protein structures in their native environment. |
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| Keywords: | in‐cell spectroscopy membrane proteins EPR spectroscopy spin labeling vitamin B12 transporter |
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