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Updated: Jun 14, 2025

Expression, Solubilization, and Purification of Eukaryotic Borate Transporters
Published on: March 7, 2019
Interdomain-linkers control conformational transitions in the SLC23 elevator transporter UraA
Benedikt T Kuhn1,2, Jonathan Zöller3, Iwan Zimmermann4
1Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany.
Interdomain-linkers in SLC23 transporters are not just flexible tethers but crucial regulators. They dictate conformational changes, influencing substrate affinity and transport rate for essential nucleobase and ascorbate uptake.
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Transport
Background:
- SLC23 transport proteins are essential for cellular uptake of nucleobases and ascorbate.
- These transporters utilize an elevator alternating-access mechanism involving two rigid domains and flexible interdomain-linkers.
Purpose of the Study:
- To investigate the role of interdomain-linkers in SLC23 transporter function.
- To elucidate how linkers regulate the conformational dynamics and transport activity of elevator transporters.
Main Methods:
- High-resolution structural determination of an inward-open SLC23 transporter conformation (UraA).
- Biochemical assays utilizing a synthetic nanobody as a conformational probe.
- Hydrogen-deuterium exchange mass spectrometry (HDX-MS) to analyze protein dynamics.
Main Results:
- Interdomain-linkers are key regulators, not passive tethers, influencing the transporter's conformational landscape.
- Linkers define the rotation axis of the mobile transport domain.
- Linkers modulate substrate affinity and transport rate, demonstrating a regulatory function.
Conclusions:
- Interdomain-linkers play a critical role in controlling the elevator alternating-access mechanism of SLC23 transporters.
- Targeting interdomain-linkers offers a potential strategy for allosteric modulation of transporter activity.
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