Structure of the P-type ATPases.

Electron cryocrystallography of precipitant-induced two-dimensional surface crystals of the neurospora plasma membrane H+ - ATPase and tubular crystals of the sarcoplasmic reticulum Ca(2+)-ATPase has recently yielded structure maps for these ion transporters at a resolution of about 8 A. The membrane-embedded regions of these closely related enzymes are similar, but the cytoplasmic regions appear to be significantly different.