No abstract

Chloride depletion blocks the normal four-step progress of photosynthetic water oxidation. We studied proton release in chloride-depleted thylakoids which were dark-adapted and excited by flashing light. Proton release was blocked from the second flash on, possibly leaving an uncompensated positive charge in the catalytic centre. The reduction of P&, by Tyrz was still very rapid (*: lo,@. From the third flash on, P&, was reduced more slowly (70 @200 ps), and by an electrogenic back-reaction. The uncompensated positive charge may be the reason why the rapid reduction of P&, by Tyrz is prevented and the transmembrane charge-pair recombination is facilitated.

No abstract