In and out of the cation pumps: P-type ATPase structure revisited.
Active transport across membranes is a crucial requirement for life. P-type ATPases build up electrochemical gradients at the expense of ATP by forming and splitting a covalent phosphoenzyme intermediate, coupled to conformational changes in the transmembrane section where the ions are translocated. The marked increment during the last three years in the number of crystal structures of P-type ATPases has greatly improved our understanding of the similarities and differences of pumps with different ion specificities, since the structures of the Ca2+-ATPase, the Na+,K+-ATPase and the H+-ATPase can now be compared directly. Mechanisms for ion gating, charge neutralization and backflow prevention are starting to emerge from comparative structural analysis; and in combination with functional studies of mutated pumps this provides a framework for speculating on how the ions are bound and released as well as on how specificity is achieved.
Bublitz
Maike
M
Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Department of Molecular Biology, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
Poulsen
Hanne
H
Morth
J Preben
JP
Nissen
Poul
P
D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D006801:Humans; D010766:Phosphorylation; D013379:Substrate Specificity
D000251:Adenosine Triphosphatases