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bioRxiv · 10.1101/2020.05.07.082438

Unlocking the reversal potential of solid supported membrane electrophysiology to determine transport stoichiometry

Henzler-Wildman, K. A.·Thomas, N. E.
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Abstract

Transport stoichiometry provides insight into the mechanism and function of ion-coupled transporters, but measuring transport stoichiometry is time-consuming and technically difficult. With the increasing evidence that many ion-coupled transporters employ multiple transport stoichiometries under different conditions, improved methods to determine transport stoichiometry are required to accurately characterize transporter activity. Reversal potential was previously shown to be a reliable, general method for determining the transport stoichiometry of ion-coupled transporters (Fitzgerald & Mindell, 2017). Here, we develop a new technique for measuring transport stoichiometry with greatly improved throughput using solid supported membrane electrophysiology (SSME). Using this technique, we are able to verify the recent report of a fixed 2:1 stoichiometry for the proton:guanidinium antiporter Gdx. Our SSME method requires only small amounts of transporter and provides a fast, easy, general method for measuring transport stoichiometry, which will facilitate future mechanistic and functional studies of ion-coupled transporters.

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Henzler-Wildman, K. A., Thomas, N. E.. 2020-05-07. Unlocking the reversal potential of solid supported membrane electrophysiology to determine transport stoichiometry. https://doi.org/10.1101/2020.05.07.082438

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