Structural basis for gating mechanism of the human sodium-potassium pump

P2-type ATPase sodium-potassium pumps (Na(+)/K(+)-ATPases) are ion-transporting enzymes that use ATP to transport Na(+) and K(+) on opposite sides of the lipid bilayer against their electrochemical gradients to maintain ion concentration gradients across the membranes in all animal cells. Despite the available molecular architecture of the Na(+)/K(+)-ATPases, a complete molecular mechanism by which the Na(+) and K(+) ions access into and are released from the pump remains unknown. Here we report five cryo-electron microscopy (cryo-EM) structures of the human alpha3 Na(+)/K(+)-ATPase in its cytoplasmic side-open (E1), ATP-bound cytoplasmic side-open (E1•ATP), ADP-AlF(4)(−) trapped Na(+)-occluded (E1•P-ADP), BeF(3)(−) trapped exoplasmic side-open (E2P) and MgF(4)(2−) trapped K(+)-occluded (E2•P(i)) states. Our work reveals the atomically resolved structural detail of the cytoplasmic gating mechanism of the Na(+)/K(+)-ATPase.