Dipolar Relaxation Dynamics at the Active Site of an ATPase Regulated by Membrane Lateral Pressure
Language English Country Germany Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
- Keywords
- fluorescence, ion pump, membrane proteins, nanodiscs, time-resolved emission,
- MeSH
- 2-Naphthylamine analogs & derivatives chemistry MeSH
- Bacterial Proteins chemistry metabolism MeSH
- Circular Dichroism MeSH
- Cysteine chemistry MeSH
- Fluorescent Dyes chemistry MeSH
- Catalytic Domain MeSH
- Legionella pneumophila enzymology MeSH
- Nanostructures chemistry MeSH
- Protein Structure, Secondary MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- 2-Naphthylamine MeSH
- 6-bromoacetyl-2-dimethylaminonaphthalene MeSH Browser
- Bacterial Proteins MeSH
- CopA protein, Bacteria MeSH Browser
- Cysteine MeSH
- Fluorescent Dyes MeSH
The active transport of ions across biological membranes requires their hydration shell to interact with the interior of membrane proteins. However, the influence of the external lipid phase on internal dielectric dynamics is hard to access by experiment. Using the octahelical transmembrane architecture of the copper-transporting P1B -type ATPase from Legionella pneumophila as a model structure, we have established the site-specific labeling of internal cysteines with a polarity-sensitive fluorophore. This enabled dipolar relaxation studies in a solubilized form of the protein and in its lipid-embedded state in nanodiscs. Time-dependent fluorescence shifts revealed the site-specific hydration and dipole mobility around the conserved ion-binding motif. The spatial distribution of both features is shaped significantly and independently of each other by membrane lateral pressure.
Institute for Experimental Physics 1 Universität Leipzig Linnéstrasse 5 04103 Leipzig Germany
J Heyrovský Inst Physical Chemistry of the A S C R v v i Prague Czech Republic
Nationales Zentrum für Tumorerkrankungen Heidelberg Im Neuenheimer Feld 460 69120 Heidelberg Germany
Technische Universität Dresden Biotechnology Center Tatzberg 47 49 01307 Dresden Germany
University of Bern Dept of Clinical Pharmacology Murtenstrasse 35 3008 Bern Switzerland
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