PXD046965

PXD046965 is an original dataset announced via ProteomeXchange.

Title	Folding of Prestin’s Anion-Binding Site and the Mechanism of Outer Hair Cell Electromotility
Description	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 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 helps define prestin’s unique voltage-sensing mechanism and electromotility.
HostingRepository	PRIDE
AnnounceDate	2023-12-06
AnnouncementXML	Submission_2023-12-06_13:33:56.801.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Xiaoxuan Lin
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: 9606;
ModificationList	No PTMs are included in the dataset
Instrument	Q Exactive

Revision	Datetime	Status	ChangeLog Entry
0	2023-11-14 14:56:05	ID requested
⏵ 1	2023-12-06 13:33:57	announced

10.7554/ELIFE.89635;

submitter keyword: hydrogen exchange, cochlear amplification, cryo-electron microscopy,mass spectrometry, voltage-sensing, protein folding

Tobin R.
contact affiliation	Department of Biochemistry and Molecular Biology, Center for Mechanical Excitability, Institute for Biophysical Dynamics, Prizker School for Molecular Engineering, The University of Chicago, Chicago, Illinois, USA
contact email	trsosnic@uchicago.edu
lab head
Xiaoxuan Lin
contact affiliation	The University of Chicago
contact email	xiaoxuanlin@uchicago.edu
dataset submitter

Dataset FTP location NOTE: Most web browsers have now discontinued native support for FTP access within the browser window. But you can usually install another FTP app (we recommend FileZilla) and configure your browser to launch the external application when you click on this FTP link. Or otherwise, launch an app that supports FTP (like FileZilla) and use this address: ftp://ftp.pride.ebi.ac.uk/pride/data/archive/2023/12/PXD046965

PRIDE project URI

• PRIDE
  1. PXD046965
     1. Label: PRIDE project
     2. Name: Folding of Prestin’s Anion-Binding Site and the Mechanism of Outer Hair Cell Electromotility