Figure 1. The reaction cycle of Na⁺,K⁺-ATPase according to the classical Post-Albers scheme²,³.

A simplified version showing only the forward direction. The ATPase in the E2· MgF₄²⁻·2K⁺ crystal is supposed to represent the E2·Pi·2K⁺ state (boxed; the product state of the hydrolysis of the aspartylphosphate). The extracellular gate of the ion pathway is open in the E2P ground state and closed in E2·2K⁺.