Numerical model for electrogenic transport by the ATP-dependent potassium pump KdpFABC.

Autor:	Hussein A; Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York., Zhang X; Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York., Stokes DL; Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York. Electronic address: stokes@nyu.edu.
Jazyk:	angličtina
Zdroj:	Biophysical reports [Biophys Rep (N Y)] 2024 Sep 11; Vol. 4 (3), pp. 100169. Date of Electronic Publication: 2024 Jun 29.
DOI:	10.1016/j.bpr.2024.100169
Abstrakt:	In vitro assays of ion transport are an essential tool for understanding molecular mechanisms associated with ATP-dependent pumps. Because ion transport is generally electrogenic, principles of electrophysiology are applicable, but conventional tools like patch-clamp are ineffective due to relatively low turnover rates of the pumps. Instead, assays have been developed to measure either voltage or current generated by transport activity of a population of molecules either in cell-derived membrane fragments or after reconstituting purified protein into proteoliposomes. In order to understand the nuances of these assays and to characterize effects of various operational parameters, we have developed a numerical model to simulate data produced by two relevant assays: fluorescence from voltage-sensitive dyes and current recorded by capacitive coupling on solid supported membranes. Parameters of the model, which has been implemented in Python, are described along with underlying principles of the computational algorithm. Experimental data from KdpFABC, a K + pump associated with P-type ATPases, are presented, and model parameters have been adjusted to mimic these data. In addition, effects of key parameters such as nonselective leak conductance and turnover rate are demonstrated. Finally, simulated data are used to illustrate the effects of capacitive coupling on measured current and to compare alternative methods for quantification of raw data. Competing Interests: Declaration of interests D.L.S. is a member of the editorial board for Biophysical Reports as well as the Publication Committee for the Biophysical Society. D.L.S. has nevertheless not been involved in the review of this manuscript. (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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