Transient and intramembrane trapping of pumped protons in thylakoids The domains are delocalized and redox-sensitive

AbstractWe measured flash-induced rapid proton release into the lumen of thylakoids. We found that the proton-trapping domains which were inducible by low concentrations of gramicidin and at alkaline pH [e.g. (1983) Biochim.Biophys.Acta 723, 294-307] were each not restricted to a particular photosystem II complex. Instead, they were delocalized. Oxidizing conditions increased the buffering capacity of the domains from approx. 5 H+ per photosystem II more than 2-fold by shifting the pK towards acidity