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Two-electron gates in photosynthesis

Conference ·
OSTI ID:6524446
Principals underlying the design of naturally occurring electron gates in the photosynthetic apparatus of green plants and photosynthetic bacteria are discussed and related to molecular electronics. A pair of quinones participates in election transfer on the reducing side of photosystem II of green plants and the photosystem found in purple photosynthetic bacteria. The quinones are photochemically reduced by electron transfers from the primary events of photosynthesis. In each quinone, there are 2 binding sites, Q1 and Q2. The quinones Q1 and Q2 are non-covalently bound to intrinsic membrane protein. Also, in both systems there is a pool of quinones of the same chemical structure which are outside the photosystem, but reside in the same membrane. Protons move from aqueous solution outside the photosynthetic membrane onto the quinone-protein complex as electrons are pumped to the quinones. The rate of proton uptake is almost two-orders of magnitude slower than electron transfer rate. Electron transfer from Q1 to Q2 is temperature dependent. Problems arising in biomimetic molecular systems are discussed. (DMC)
Research Organization:
Argonne National Lab., IL (USA)
OSTI ID:
6524446
Report Number(s):
CONF-8103158-2; ON: DE83007779
Country of Publication:
United States
Language:
English