DIRECT INDICATION FOR THE EXISTENCE OF A DOUBLE STALK IN CF0F1

The H+-ATPase from chloroplasts (CF0F1) was investigated by electron m icroscopy of negatively stained single molecules followed by image pro cessing. The analysis of about 4700 particles from 72 micrographs gave clear evidence that the membrane-integrated F-0 part is connected by at least two stalks to the F-1 part. One of the two stalks is more pro minent and connects a central part of F-1 with a slightly peripheral p art of F-0. The other stalk connects a peripheral part of F-1 to a per ipheral part of F-1. (C) Academic Press.