Our major aim is to elucidate the structure and function of the Escherichia coli coupling factor, F1-ATPase. We will complete purification of a large collection of monoclonal antibodies, directed against the Alpha, Beta, Gamma, Delta, and Epsilon subunits. They will be used to define peptide domains of interest, and to locate exposed parts of F1-ATPase, both for the soluble and the membrane-bound enzyme. We plan to study the assembly of F1-ATPase and to look for evidence of regulation. In other studies, external ATP was seen to cause entry of Na+, exit of K+ and hydrolysis of 1/3 of intracellular ATP in transformed mouse cells. Following this, they became permeable to nucleotides and phosphate esters. We have evidence that Ca++ is involved and plan to use ion selective electrodes and Ca++ indicators such as """"""""quin-2"""""""". Effects of calmodulin on ATP permeabilization will be further examined and mutant studies are underway. Similarities and differences between ATP and ionophore permeabilization will be explored and we aim to get membrane vesicles sensitive to external ATP.
