Photosystems and global effects of oxygenic photosynthesis

Nathan Nelson*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review


Because life on earth is governed by the second law of thermodynamics, it is subject to increasing entropy. Oxygenic photosynthesis, the earth's major producer of both oxygen and organic matter, is a principal player in the development and maintenance of life, and thus results in increased order. The primary steps of oxygenic photosynthesis are driven by four multi-subunit membrane protein complexes: photosystem I, photosystem II, cytochrome b 6f complex, and F-ATPase. Photosystem II generates the most positive redox potential found in nature and thus capable of extracting electrons from water. Photosystem I generates the most negative redox potential found in nature; thus, it largely determines the global amount of enthalpy in living systems. The recent structural determination of PSII and PSI complexes from cyanobacteria and plants sheds light on the evolutionary forces that shaped oxygenic photosynthesis. This newly available structural information complements knowledge gained from genomic and proteomic data, allowing for a more precise description of the scenario in which the evolution of life systems took place. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.

Original languageEnglish
Pages (from-to)856-863
Number of pages8
JournalBiochimica et Biophysica Acta - Bioenergetics
Issue number8
StatePublished - Aug 2011


FundersFunder number
The United States–Israel Agricultural Research and Development Fund
Israel Science Foundation204-10, IS-4229-09


    • Earth
    • Evolution
    • Oxygen
    • Photosynthesis
    • Photosystem
    • Structure


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