Fig. 2: Cryo-EM maps and structures of the human α3 Na⁺/K⁺ ATPase in its Na⁺- and K⁺-occluded states.

a 3.7 Å- resolution cryo-EM map of the human α3 Na⁺-occluded structure. exo: exoplasm, cyto: cytoplasm. b 4.1 Å- resolution cryo-EM map of the human α3 K⁺-occluded structure. exo: exoplasm, cyto: cytoplasm. c ADP-AlF₄⁻ trapped cytoplasmic domains of the Na⁺-occluded structure. The mesh represents electron density of ADP-AlF₄⁻ d MgF₄²⁻ trapped cytoplasmic domains of the K⁺-occluded-state structure. The mesh represents electron density of MgF₄²⁻. e Structural model of the human α3 Na⁺/K⁺ ATPase in its Na⁺-occluded state. The black dashed line represents missing density of amino acid residues 261–270 in the structural model. f Structural model of the human α3 Na⁺/K⁺-ATPase in its K⁺-occluded state. g, h Densities of the cation-binding residues and their respective helices in the Na⁺-occluded (g) and K⁺-occluded structure (h).