Modulation of the Na,K-ATPase by Magnesium Ions

Apell, Hans-Jürgen; Hitzler, Tanja; Schreiber, Grischa

Modulation of the Na,K-ATPase by Magnesium Ions

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Date

2017

Authors

Apell, Hans-Jürgen

Hitzler, Tanja

Schreiber, Grischa

DOI (citable link)

10.1021/acs.biochem.6b01243

Collections

Biologie

Publication type

Journal article

Publication status

Published

Published in

Biochemistry ; 56 (2017), 7. - pp. 1005-1016. - ISSN 0006-2960. - eISSN 1520-4995

Abstract

Since the beginning of investigations of the Na,K-ATPase, it has been well-known that Mg²⁺ is an essential cofactor for activation of enzymatic ATP hydrolysis without being transported through the cell membrane. Moreover, experimental evidence has been collected through the years that shows that Mg²⁺ ions have a regulatory effect on ion transport by interacting with the cytoplasmic side of the ion pump. Our experiments allowed us to reveal the underlying mechanism. Mg²⁺ is able to bind to a site outside the membrane domain of the protein's α subunit, close to the entrance of the access channel to the ion-binding sites, thus modifying the local concentration of the ions in the electrolyte, of which Na⁺, K⁺, and H⁺ are of physiological interest. The decrease in the concentration of these cations can be explained by electrostatic interaction and estimated by the Debye-Hückel theory. This effect provokes the observed apparent reduction of the binding affinity of the binding sites of the Na,K-ATPase in the presence of various Mg²⁺ concentrations. The presence of the bound Mg²⁺, however, does not affect the reaction kinetics of the transport function of the ion pump. Therefore, stopped-flow experiments could be performed to gain the first insight into the Na⁺ binding kinetics on the cytoplasmic side by Mg²⁺ concentration jump experiments.

Subject (DDC)

570 Biosciences, Biology

Cite This

ISO 690

APELL, Hans-Jürgen, Tanja HITZLER, Grischa SCHREIBER, 2017. Modulation of the Na,K-ATPase by Magnesium Ions. In: Biochemistry. 56(7), pp. 1005-1016. ISSN 0006-2960. eISSN 1520-4995. Available under: doi: 10.1021/acs.biochem.6b01243

BibTex

@article{Apell2017-02-21Modul-37889,
  year={2017},
  doi={10.1021/acs.biochem.6b01243},
  title={Modulation of the Na,K-ATPase by Magnesium Ions},
  number={7},
  volume={56},
  issn={0006-2960},
  journal={Biochemistry},
  pages={1005--1016},
  author={Apell, Hans-Jürgen and Hitzler, Tanja and Schreiber, Grischa}
}

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