Structure of V-type ATPase from Clostridium fervidus by electron microscopy

F-type and V-type ATPases couple synthesis or hydrolysis of ATP to the tran slocation of H+ or Na+ across biological membranes and have similarities in structure and mechanism. In both types of enzymes three main parts can be distinguished: headpiece, membrane-bound piece and stalk region. We report on structural details of the membrane sector and stalk region, including th e stator, of V-type ATPase from Clostridium fervidus, as determined by elec tron microscopy. Besides visualization of the stator structure, one of the main findings is that in certain projections the central stalk connecting V -1 and V-0 makes an angle of about 70 degrees with the membrane. Implicatio ns for the subunit arrangement in V-type and F-type ATPase are discussed.