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. 1971 Jan;68(1):16–19. doi: 10.1073/pnas.68.1.16

Primary Reactions of Photosynthesis: Photoreduction of a Bound Chloroplast Ferredoxin at Low Temperature as Detected by EPR Spectroscopy

R Malkin 1, Alan J Bearden 1,*
PMCID: PMC391091  PMID: 4322259

Abstract

An electron paramagnetic resonance signal was observed at 25°K in whole spinach chloroplasts after illumination at 77°K. The light-induced epr spectrum had g-values (gx = 1.86, gy = 1.94, gz = 2.05) and a temperature dependence that were characteristic of the reduced state of a plant-type ferredoxin. The light-induced epr spectrum was also observed in broken spinach chloroplasts from which soluble ferredoxin was removed. Chemical analyses showed that both whole and broken spinach chloroplasts contained amounts of nonheme iron and “acid-labile sulfide” consistent with the presence of a bound iron-sulfur protein, at a level of about one molecule per 75 chlorophyll molecules. These results support the conclusion that chloroplasts contain a bound ferredoxin that may serve as a primary low-potential electron acceptor in photosynthesis.

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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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