دورية أكاديمية
Folding of prestin’s anion-binding site and the mechanism of outer hair cell electromotility
| العنوان: | Folding of prestin’s anion-binding site and the mechanism of outer hair cell electromotility |
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| المؤلفون: | Xiaoxuan Lin, Patrick R Haller, Navid Bavi, Nabil Faruk, Eduardo Perozo, Tobin R Sosnick |
| المصدر: | eLife, Vol 12 (2023) |
| بيانات النشر: | eLife Sciences Publications Ltd, 2023. |
| سنة النشر: | 2023 |
| المجموعة: | LCC:Medicine LCC:Science LCC:Biology (General) |
| مصطلحات موضوعية: | mass spectrometry, hydrogen exchange, cochlear amplification, protein folding, voltage sensing, cryo-electron microscopy, Medicine, Science, Biology (General), QH301-705.5 |
| الوصف: | Prestin responds to transmembrane voltage fluctuations by changing its cross-sectional area, a process underlying the electromotility of outer hair cells and cochlear amplification. Prestin belongs to the SLC26 family of anion transporters yet is the only member capable of displaying electromotility. Prestin’s voltage-dependent conformational changes are driven by the putative displacement of residue R399 and a set of sparse charged residues within the transmembrane domain, following the binding of a Cl− anion at a conserved binding site formed by the amino termini of the TM3 and TM10 helices. However, a major conundrum arises as to how an anion that binds in proximity to a positive charge (R399), can promote the voltage sensitivity of prestin. Using hydrogen–deuterium exchange mass spectrometry, we find that prestin displays an unstable anion-binding site, where folding of the amino termini of TM3 and TM10 is coupled to Cl− binding. This event shortens the TM3–TM10 electrostatic gap, thereby connecting the two helices, resulting in reduced cross-sectional area. These folding events upon anion binding are absent in SLC26A9, a non-electromotile transporter closely related to prestin. Dynamics of prestin embedded in a lipid bilayer closely match that in detergent micelle, except for a destabilized lipid-facing helix TM6 that is critical to prestin’s mechanical expansion. We observe helix fraying at prestin’s anion-binding site but cooperative unfolding of multiple lipid-facing helices, features that may promote prestin’s fast electromechanical rearrangements. These results highlight a novel role of the folding equilibrium of the anion-binding site, and help define prestin’s unique voltage-sensing mechanism and electromotility. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 2050-084X |
| Relation: | https://elifesciences.org/articles/89635; https://doaj.org/toc/2050-084X |
| DOI: | 10.7554/eLife.89635 |
| URL الوصول: | https://doaj.org/article/171cf7e90fbe4af1886a08282c50d10e |
| رقم الأكسشن: | edsdoj.171cf7e90fbe4af1886a08282c50d10e |
| قاعدة البيانات: | Directory of Open Access Journals |
Full Text Finder | تدمد: | 2050084X |
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| DOI: | 10.7554/eLife.89635 |