Relationship between the oxidation potential of the bacteriochlorophyll dimer and electron transfer in photosynthetic reaction centers

James Paul Allen, J. C. Williams

Research output: Contribution to journalArticle

81 Citations (Scopus)

Abstract

The primary electron donor in the photosynthetic reaction center from purple bacteria is a bacteriochlorophyll dimer containing four conjugated carbonyl groups that may form hydrogen bonds with amino acid residues. Spectroscopic analyses of a set of mutant reaction centers confirm that hydrogen bonds can be formed between each of these carbonyl groups and histidine residues in the reaction center subunits. The addition of each hydrogen bond is correlated with an increase in the oxidation potential of the dimer, resulting in a 355-mV range in the midpoint potential. The resulting changes in the free-energy differences for several reactions involving the dimer are related to the electron transfer rates using the Marcus theory. These reactions include electron transfer from cytochrome c2 to the oxidized dimer, charge recombination from the primary electron acceptor quinone, and the initial forward electron transfer.

Original languageEnglish
Pages (from-to)275-283
Number of pages9
JournalJournal of Bioenergetics and Biomembranes
Volume27
Issue number3
DOIs
Publication statusPublished - Jun 1995

Fingerprint

Photosynthetic Reaction Center Complex Proteins
Bacteriochlorophylls
Electrons
Hydrogen
Cytochromes c2
Proteobacteria
Histidine
Genetic Recombination
Amino Acids

Keywords

  • Bacterial photosynthesis
  • cytochrome
  • hydrogen bond
  • infrared spectroscopy, membrane protein
  • purple bacteria
  • site-directed mutagenesis

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

Cite this

@article{cd208ea3256442af8cc53bcc785a45a1,
title = "Relationship between the oxidation potential of the bacteriochlorophyll dimer and electron transfer in photosynthetic reaction centers",
abstract = "The primary electron donor in the photosynthetic reaction center from purple bacteria is a bacteriochlorophyll dimer containing four conjugated carbonyl groups that may form hydrogen bonds with amino acid residues. Spectroscopic analyses of a set of mutant reaction centers confirm that hydrogen bonds can be formed between each of these carbonyl groups and histidine residues in the reaction center subunits. The addition of each hydrogen bond is correlated with an increase in the oxidation potential of the dimer, resulting in a 355-mV range in the midpoint potential. The resulting changes in the free-energy differences for several reactions involving the dimer are related to the electron transfer rates using the Marcus theory. These reactions include electron transfer from cytochrome c2 to the oxidized dimer, charge recombination from the primary electron acceptor quinone, and the initial forward electron transfer.",
keywords = "Bacterial photosynthesis, cytochrome, hydrogen bond, infrared spectroscopy, membrane protein, purple bacteria, site-directed mutagenesis",
author = "Allen, {James Paul} and Williams, {J. C.}",
year = "1995",
month = "6",
doi = "10.1007/BF02110097",
language = "English",
volume = "27",
pages = "275--283",
journal = "Journal of Bioenergetics and Biomembranes",
issn = "0145-479X",
publisher = "Springer New York",
number = "3",

}

TY - JOUR

T1 - Relationship between the oxidation potential of the bacteriochlorophyll dimer and electron transfer in photosynthetic reaction centers

AU - Allen, James Paul

AU - Williams, J. C.

PY - 1995/6

Y1 - 1995/6

N2 - The primary electron donor in the photosynthetic reaction center from purple bacteria is a bacteriochlorophyll dimer containing four conjugated carbonyl groups that may form hydrogen bonds with amino acid residues. Spectroscopic analyses of a set of mutant reaction centers confirm that hydrogen bonds can be formed between each of these carbonyl groups and histidine residues in the reaction center subunits. The addition of each hydrogen bond is correlated with an increase in the oxidation potential of the dimer, resulting in a 355-mV range in the midpoint potential. The resulting changes in the free-energy differences for several reactions involving the dimer are related to the electron transfer rates using the Marcus theory. These reactions include electron transfer from cytochrome c2 to the oxidized dimer, charge recombination from the primary electron acceptor quinone, and the initial forward electron transfer.

AB - The primary electron donor in the photosynthetic reaction center from purple bacteria is a bacteriochlorophyll dimer containing four conjugated carbonyl groups that may form hydrogen bonds with amino acid residues. Spectroscopic analyses of a set of mutant reaction centers confirm that hydrogen bonds can be formed between each of these carbonyl groups and histidine residues in the reaction center subunits. The addition of each hydrogen bond is correlated with an increase in the oxidation potential of the dimer, resulting in a 355-mV range in the midpoint potential. The resulting changes in the free-energy differences for several reactions involving the dimer are related to the electron transfer rates using the Marcus theory. These reactions include electron transfer from cytochrome c2 to the oxidized dimer, charge recombination from the primary electron acceptor quinone, and the initial forward electron transfer.

KW - Bacterial photosynthesis

KW - cytochrome

KW - hydrogen bond

KW - infrared spectroscopy, membrane protein

KW - purple bacteria

KW - site-directed mutagenesis

UR - http://www.scopus.com/inward/record.url?scp=0028783670&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028783670&partnerID=8YFLogxK

U2 - 10.1007/BF02110097

DO - 10.1007/BF02110097

M3 - Article

C2 - 8847341

AN - SCOPUS:0028783670

VL - 27

SP - 275

EP - 283

JO - Journal of Bioenergetics and Biomembranes

JF - Journal of Bioenergetics and Biomembranes

SN - 0145-479X

IS - 3

ER -