Conformational heterogeneity of the aspartate transporter Glt(Ph)
| Autor: | Heinz-Juergen Steinhoff, Dirk Jan Slotboom, Dorith Wunnicke, Inga Hänelt, Enrica Bordignon |
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| Přispěvatelé: | Enzymology, Groningen Biomolecular Sciences and Biotechnology, Zernike Institute for Advanced Materials, Molecular Microbiology |
| Rok vydání: | 2012 |
| Předmět: |
Models
Molecular Stereochemistry Amino Acid Transport Systems Acidic Protein Conformation Archaeal Proteins law.invention 03 medical and health sciences Pyrococcus horikoshii MOVEMENT 0302 clinical medicine SUBSTRATE Structural Biology law BINDING Electron paramagnetic resonance Molecular Biology 030304 developmental biology 0303 health sciences Aspartic Acid Binding Sites biology Chemistry Excitatory amino-acid transporter Spectrum Analysis Sodium GATE Electron Spin Resonance Spectroscopy Substrate (chemistry) Transporter GLUTAMATE TRANSPORTER biology.organism_classification HOMOLOG Protein Subunits Mutagenesis biology.protein Protein Multimerization 030217 neurology & neurosurgery PYROCOCCUS-HORIKOSHII |
| Zdroj: | Nature Structural & Molecular Biology, 20(2), 210-214. Nature Publishing Group |
| ISSN: | 1545-9985 1545-9993 |
| Popis: | Glt(Ph) is a Pyrococcus horikoshii homotrimeric Na+-coupled aspartate transporter that belongs to the glutamate transporter family. Each protomer consists of a trimerization domain involved in subunit interaction and a transporting domain with the substrate-binding site. Here, we have studied the conformational changes underlying transport by Gltph using [PR spectroscopy. The trimerization domains form a rigid scaffold, whereas the transporting domains sample multiple conformations, consistent with large-scale movements during the transport cycle. Binding of substrates changed the occupancies of the different conformational states, but the domains remained heterogeneous. The membrane environment favored conformations different from those observed in detergent micelles, but the transporting domain remained structurally heterogeneous in both environments. We conclude that the transporting domains sample multiple conformational states with substantial occupancy regardless of the presence of substrate and coupling ions, consistent with equilibrium constants close to unity between the observed transporter conformations. |
| Databáze: | OpenAIRE |
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