title: Energy-dependent changes in the conformation of the epsilon subunit of the chloroplast ATP synthase.
abstract: Rabbit antiserum raised against the isolated native epsilon subunit of the chloroplast coupling factor 1 activated the ATPase activity of coupling factor 1 in solution by removing the epsilon subunit. Incubation of thylakoid membranes with the antiserum in the dark had no effect on photophosphorylation or on the dithiothreitol-induced Mg2+-ATPase activity. Incubation with the antiserum during illumination, however, strongly inhibited both activities and caused the membranes to become leaky to protons. The results indicate that the formation of a proton gradient across the thylakoid membrane induces a change in conformation of the epsilon subunit of the ATP synthase such that it becomes susceptible to attack and removal by the antibodies. This change may be a part of the mechanism that results in energy-dependent activation of the ATP synthase.
mesh_terms: D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002736:Chloroplasts / Q000201:enzymology*; D007106:Immune Sera; D007425:Intracellular Membranes / Q000201:enzymology; D007700:Kinetics; D008027:Light; D046911:Macromolecular Substances; D010944:Plants / Q000201:enzymology; D011487:Protein Conformation; D013816:Thermodynamics
chemical_list: D007106:Immune Sera; D046911:Macromolecular Substances; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases