Direct indication for the existence of a double stalk in CF0F1.

The H+-ATPase from chloroplasts (CF0F1) was investigated by electron microscopy of negatively stained single molecules followed by image processing. The analysis of about 4700 particles from 72 micrographs gave clear evidence that the membrane-integrated F0 part is connected by at least two stalks to the F1 part. One of the two stalks is more prominent and connects a central part of F1 with a slightly peripheral part of F0. The other stalk connects a peripheral part of F1 to a peripheral part of F0.