The objects of this proposal are the isolation, characterization and reconstitution of the subunits of the R. rubrum coupling factor (ATPase) and transhydrogenase factor (TH) in order to understand the structural organization of these complex proteins and to relate structure to functional organization on the membrane. Arylazido-beta-anlanyl photoaffinity analogues of ATP, ADP, NAD ion and NADP ion developed in this laboratory are being used together with a variety of physiological and nonphysiological conditions to bring about specific and irreversible interactions between the two proteins and the nucleotide analogues. The reconstituted energy (ATP) dependent transhydration can be used to evaluate the effect of specific modifications of the coupling ATPase on the ability of the membrane system to drive energy dissipative (i.e. energy requiring) reactions. In a like manner the level of photophosphorylation (which requires participation of the coupling factor) is being used to monitor the ability for the membrane system to bring about energy conservation as a function of the specificity of coupling factor modifications.