Crystal Structures of Ca2+-ATPase in Various Physiological States
The structures of the Ca2+-ATPase (SERCA1a) in different physiological states were determined by X-ray crystallography. Detailed comparison of the structures in the Ca2+-bound form and unbound (but thapsigargin bound) form reveals that very large rearrangements of the transmembrane helices take place accompanying Ca2+ dissociation and binding and that they are mechanically linked with equally large movements of the cytoplasmic domains. The meaning of the rearrangement of the transmembrane helices becomes apparent by homology modeling of the Na+K+-ATPase.
crystal structure ca2+-atpase serca1a crystallography homology modeling phospholipid transmembrane helix ca2+-binding sites domain movements