InterPro domain: IPR023299

P-ATPases (also known as E1-E2 ATPases) ([intenz:3.6.3.-]) are found in bacteria and in a number of eukaryotic plasma membranes and organelles [ 1 ]. P-ATPases function to transport a variety of different compounds, including ions and phospholipids, across a membrane using ATP hydrolysis for energy. There are many different classes of P-ATPases, which transport specific types of ion: H ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , Ag ⁺ and Ag ²⁺ , Zn ²⁺ , Co ²⁺ , Pb ²⁺ , Ni ²⁺ , Cd ²⁺ , Cu ⁺ and Cu ²⁺ . P-ATPases can be composed of one or two polypeptides, and can usually assume two main conformations called E1 and E2.

This superfamily represents the cytoplasmic domain N found in P-type ATPases. The cytoplasmic loops of the P-type ATPases form three separate modules, commonly named the A, P and N-domains [ 2 , 3 . The N-domain comprises the nucleotide binding site [ 4 ]. This domain forms a seven-stranded antiparallel beta-sheet with two additional beta-strands forming a hairpin and five alpha-helices [ 5 ].

1. Evolution of substrate specificities in the P-type ATPase superfamily. J. Mol. Evol. 46, 84-101
2. Lumenal gating mechanism revealed in calcium pump crystal structures with phosphate analogues. Nature 432, 361-8
3. Improved Model of Proton Pump Crystal Structure Obtained by Interactive Molecular Dynamics Flexible Fitting Expands the Mechanistic Model for Proton Translocation in P-Type ATPases. Front Physiol 8, 202
4. Inter-domain motions of the N-domain of the KdpFABC complex, a P-type ATPase, are not driven by ATP-induced conformational changes. J. Mol. Biol. 342, 1547-58
5. The crystallographic structure of Na,K-ATPase N-domain at 2.6A resolution. J. Mol. Biol. 332, 1175-82