Ion Binding and Selectivity of the Na⁺/H⁺ Antiporter MjNhaP1 from Experiment and Simulation.

ABSTRACT: Cells employ membrane-embedded antiporter proteins to control their pH, salt concentration, and volume. The large family of cation/proton antiporters is dominated by Na⁺/H⁺ antiporters that exchange sodium ions against protons, but homologous K⁺/H⁺ exchangers have recently been characterized. We show experimentally that the electroneutral antiporter NhaP1 of Methanocaldococcus jannaschii (MjNhaP1) is highly selective for Na⁺ ions. We then characterize the ion selectivity in both the inward-open and outward-open states of MjNhaP1 using classical molecular dynamics simulations, free energy calculations, and hybrid quantum/classical (QM/MM) simulations. We show that MjNhaP1 is highly selective for binding of Na⁺ over K

SUBMITTER: Warnau J 

PROVIDER: S-EPMC6970264 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature