Interaction of photosystem I-derived protons with the water-splitting enzyme complex. Evidence for localized domains.

摘要: The induction of millisecond delayed fluorescence mediated by PS I-dependent proton pumping has been used as an indicator the time course with which those protons equilibrate sites on oxygen-evolving enzyme complex (Bowes, J. M., and Crofts, A. R. (1978).Z. Naturforsch.33C, 271–275). We found that curves were retarded a reversible exposure non-energized thylakoids to low concentrations uncoupler, desaspidin, at alkaline, but not neutral, pH. increasing buffering capacity thylakoid lumen Tricine, inhibited energy transfer inhibitors, dicyclohexylcarbodiimide (DCCD) triphenyltin chloride (TPT). These data suggest (i) catalytic site water-splitting is located in proton-sequestering membrane domains, rather than lumen-exposed inner surface, (ii) released during I-mediated electron transport might protonatable without passing through lumen, (iii) may travel over specific conducting pathways can be blocked DCCD TPT.