Glutamate Water Gates in the Ion Binding Pocket of Na⁺ Bound Na⁺, K⁺-ATPase.

ABSTRACT: The dynamically changing protonation states of the six acidic amino acid residues in the ion binding pocket of the Na⁺, K⁺ -ATPase (NKA) during the ion transport cycle are proposed to drive ion binding, release and possibly determine Na⁺ or K⁺ selectivity. We use molecular dynamics (MD) and density functional theory (DFT) simulations to determine the protonation scheme of the Na⁺ bound conformation of NKA. MD simulations of all possible protonation schemes show that the bound Na⁺ ions are most stably bound when three or four protons reside in the binding sites, and that Glu954 in site III is always protonated. Glutamic acid residues in the three binding sites act as water gates, and their deprotonation triggers water entry t

SUBMITTER: Han M 

PROVIDER: S-EPMC5233988 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature