Abstract
In photosynthetic organisms, solar energy drives electron and proton transfer reactions across cell membranes in order to create energy-rich compounds. These reactions are performed by pigment-protein complexes, including bacterial reaction centers and photosystem II. In this chapter we discuss how electron transfer is determined by the transition energies and oxidation-reduction midpoint potentials of the cofactors and how protein environments can alter the energetics of these cofactors, in particular the primary electron donors, the bacteriochlorophyll dimer of reaction centers and P680 of photosystem II. A Hückel model is presented that provides an accurate description of the electronic structure of the bacteriochlorophyll dimer, including why specific protein interactions, namely, electrostatic and hydrogen bonding interactions, alter not only the oxidation-reduction midpoint potentials but also the electron spin distribution. A special focus is placed on how protein environments can create strong oxidants, including the ability of photosystem II to perform the highly oxidizing reactions needed to oxidize water and the involvement of the Mn4Ca cluster in this process.
| Original language | English |
|---|---|
| Title of host publication | The Biophysics of Photosynthesis |
| Publisher | Springer New York |
| Pages | 275-295 |
| Number of pages | 21 |
| ISBN (Electronic) | 9781493911486 |
| ISBN (Print) | 9781493911479 |
| DOIs | |
| Publication status | Published - Jan 1 2014 |
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Keywords
- Bacteriochlorophyll
- Bacteriochlorophyll dimer
- Bacteriopheophytin
- Chlorophyll
- Electron transfer
- Manganese cluster
- Oxidation-reduction potential
- Photosystem II
- Reaction centers
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
Cite this
Energetics of cofactors in photosynthetic complexes : Relationship between protein-cofactor interactions and midpoint potentials. / Allen, James Paul; Williams, Jo Ann C.
The Biophysics of Photosynthesis. Springer New York, 2014. p. 275-295.Research output: Chapter in Book/Report/Conference proceeding › Chapter
}
TY - CHAP
T1 - Energetics of cofactors in photosynthetic complexes
T2 - Relationship between protein-cofactor interactions and midpoint potentials
AU - Allen, James Paul
AU - Williams, Jo Ann C.
PY - 2014/1/1
Y1 - 2014/1/1
N2 - In photosynthetic organisms, solar energy drives electron and proton transfer reactions across cell membranes in order to create energy-rich compounds. These reactions are performed by pigment-protein complexes, including bacterial reaction centers and photosystem II. In this chapter we discuss how electron transfer is determined by the transition energies and oxidation-reduction midpoint potentials of the cofactors and how protein environments can alter the energetics of these cofactors, in particular the primary electron donors, the bacteriochlorophyll dimer of reaction centers and P680 of photosystem II. A Hückel model is presented that provides an accurate description of the electronic structure of the bacteriochlorophyll dimer, including why specific protein interactions, namely, electrostatic and hydrogen bonding interactions, alter not only the oxidation-reduction midpoint potentials but also the electron spin distribution. A special focus is placed on how protein environments can create strong oxidants, including the ability of photosystem II to perform the highly oxidizing reactions needed to oxidize water and the involvement of the Mn4Ca cluster in this process.
AB - In photosynthetic organisms, solar energy drives electron and proton transfer reactions across cell membranes in order to create energy-rich compounds. These reactions are performed by pigment-protein complexes, including bacterial reaction centers and photosystem II. In this chapter we discuss how electron transfer is determined by the transition energies and oxidation-reduction midpoint potentials of the cofactors and how protein environments can alter the energetics of these cofactors, in particular the primary electron donors, the bacteriochlorophyll dimer of reaction centers and P680 of photosystem II. A Hückel model is presented that provides an accurate description of the electronic structure of the bacteriochlorophyll dimer, including why specific protein interactions, namely, electrostatic and hydrogen bonding interactions, alter not only the oxidation-reduction midpoint potentials but also the electron spin distribution. A special focus is placed on how protein environments can create strong oxidants, including the ability of photosystem II to perform the highly oxidizing reactions needed to oxidize water and the involvement of the Mn4Ca cluster in this process.
KW - Bacteriochlorophyll
KW - Bacteriochlorophyll dimer
KW - Bacteriopheophytin
KW - Chlorophyll
KW - Electron transfer
KW - Manganese cluster
KW - Oxidation-reduction potential
KW - Photosystem II
KW - Reaction centers
UR - http://www.scopus.com/inward/record.url?scp=85015658515&partnerID=8YFLogxK
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U2 - 10.1007/978-1-4939-1148-6_9
DO - 10.1007/978-1-4939-1148-6_9
M3 - Chapter
SN - 9781493911479
SP - 275
EP - 295
BT - The Biophysics of Photosynthesis
PB - Springer New York
ER -