Mechanistic principles of ion transport in the Na,K-ATPase

Abstract

The Na,K-ATPase is a member of the P-type ATPase family and a primary active ion transporter for Na⁺ and K⁺ ions in the cytoplasmic membrane of virtually all animal cells. Considerable progress in understanding the ion-pump mechanism of the Na,K-ATPase was gained by combining biophysical and biochemical studies of more than 30 years with structural information at atomic resolution available since recent years. Biophysical studies have revealed detailed properties of the ion movements that led to a gated-channel model which is strongly supported by structural findings obtained for the sodium pump. The basic question of how the free Gibbs energy released by ATP hydrolysis is transferred to the protein and transformed into uphill transport of the ions is still without reply.