The mechanism of proton-linked ATP synthesis by chloroplast, mitochondrial and bacterial membranes is a major unsolved problem in biochemistry. This award is aimed at determining whether the unusual asymmetry of this enzyme is altered by catalytic turnover. The roles of the delta subunit of the enzyme and its position in the macromolecule will be elucidated. Interaction between the gamma and epsilon subunits will be further investigated since these polypeptides play critical roles in the regulation of the enzyme's activity. Structural changes in the enzyme are induced by the formation of electrochemical proton gradients across the thylakoid membrane. Attempts to map these changes and to follow them kinetically will be made. This research will provide vital information to help us understand how energy is stored in living cells by the synthesis of an energy rich compound, adenosine triphosphate (ATP).