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Energy transduction by the photosynthetic reaction center complex from Rhodopseudomonas viridis
Author(s) -
Skulachev Vladimir P.
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)81120-1
Subject(s) - photosynthetic reaction centre , bacteriochlorophyll , chemistry , dimer , heme , photochemistry , excited state , electron transfer , proton , photosynthesis , electron transport chain , atomic physics , physics , biochemistry , organic chemistry , quantum mechanics , enzyme
Comparison of data of (i) the high‐resolution X‐ray analysis of the Rhodopseudomonas viridis reaction center complex and (ii) direct (with a voltmeter) measurement of charge displacement in the same complex is presented. It is revealed that 95% of the energy stored in the form of the membrane electric potential is due to electron and 5% to proton transfers. Five stages of the overall process were found to contribute to the light‐induced membrane charging, namely electron transfers from excited bacteriochlorophyll dimer to bacteriopheophytin, from bacteriopheophytin to MQ, from heme c ‐559 to bacteriochlorophyll dimer, from heme c ‐556 to heme c ‐559 and H + transfer from cytoplasmic water to the bound CoQ. The contribution of each stage to the energy storage depends upon the dielectric constant value in the respective part of the complex rather than upon the distance covered by the electron or proton. It appears to be higher, the deeper the redox groups involved are immersed into the membrane.