Analyzing conformational changes in single FRET-labeled A_1 parts of archaeal A_1A_O-ATP synthase

摘要

ATP synthases utilize a proton motive force to synthesize ATP. In reverse, these membrane-embedded enzymes can also hydrolyze ATP to pump protons over the membrane. To prevent wasteful ATP hydrolysis, distinct control mechanisms exist for ATP synthases in bacteria, archaea, chloroplasts and mitochondria. Single-molecule Foerster resonance energy transfer (smFRET) demonstrated that the C-terminus of the rotary subunit e in the Escherichia coli enzyme changes its conformation to block ATP hydrolysis. Previously, we investigate the related conformational changes of subunit F of the A_1A_O-ATP synthase from the archaeon Methanosarcina mazei Goel. Here, we analyzed the lifetimes of fluorescence donor and acceptor dyes to distinguish between smFRET signals of conformational changes and potential artefacts.