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Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1975 Dec;72(12):4956–4960. doi: 10.1073/pnas.72.12.4956

Primary charge separation in bacterial photosynthesis: oxidized chlorophylls and reduced pheophytin.

J Fajer, D C Brune, M S Davis, A Forman, L D Spaulding
PMCID: PMC388853  PMID: 174084

Abstract

Bacteriopheophytin, the magnesium-free base of bacteriochlorophyll, undergoes reversible one-electron reduction in organic solvents to yield an anionic free radical with characteristic optical and electron spin resonance spectra. The reduction potential of bacteriopheophytin, E1/2 approximately --0.55 V against a normal hydrogen electrode, compared to E1/2 approximately --0.85 V for bacteriochlorophyll, renders it a likely electron acceptor in the primary charge separation of photosynthesis. Comparison of these data with picosecond optical changes recently observed upon pulsed laser excitation of bacterial reaction centers leads us to propose that bacteriopheophytin is indeed a transient electron acceptor and that the primary charge separation of bacterial photosynthesis occurs between the bacteriochlorophyll complex P870 and bacteriopheophytin to yield the radicals of the oxidized chlorophyll dimer cation and reduced pheophytin anion.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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