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. 1976 Apr;73(4):1196–1198. doi: 10.1073/pnas.73.4.1196

Proton relaxation and charge accumulation during oxygen evolution in photosynthesis

T Wydrzynski *, N Zumbulyadis †, P G Schmidt †, H S Gutowsky †, Govindjee *
PMCID: PMC430228  PMID: 16592306

Abstract

The water proton spin-spin (transverse) relaxation rate of chloroplast suspensions has been measured after each of a series of 2.4 μsec light flashes. The sequence of relaxation rates shows a damped oscillatory pattern with a period of four and peaks after the 3rd, 7th, 11th, and 15th flashes. This result indicates that water proton relaxation can be used to monitor the charge-accumulating states as postulated by Kok and coworkers for the oxygen-evolving mechanism in green plants [(1970) Photochem. Photobiol. 11, 457-475]. Other experiments [Wydrzynski et al. (1975) Biochim. Biophys. Acta 408, 349-354] have shown that the proton relaxation rate is strongly influenced by membrane-bound manganese in various oxidation states, suggesting that manganese participates in the charge accumulation process during oxygen evolution.

Keywords: nuclear magnetic resonance, manganese in chloroplasts

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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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