Structure-based calculations of optical spectra of photosystem i suggest an asymmetric light-harvesting process

Julian Adolphs, Frank Müh, Mohamed Madjet, Marcel Schmidt Am Busch, Thomas Renger

Research output: Contribution to journalArticle

70 Citations (Scopus)

Abstract

Optical line shape theory is combined with a quantum-chemical/electrostatic calculation of the site energies of the 96 chlorophyll a pigments and their excitonic couplings to simulate optical spectra of photosystem I core complexes from Thermosynechococcus elongatus. The absorbance, linear dichroism and circular dichroism spectra, calculated on the basis of the 2.5 Å crystal structure, match the experimental data semiquantitatively allowing for a detailed analysis of the pigment-protein interaction. The majority of site energies are determined by multiple interactions with a large number (>20) of amino acid residues, a result which demonstrates the importance of long-range electrostatic interactions. The low-energy exciton states of the antenna are found to be located at a nearest distance of about 25 Å from the special pair of the reaction center. The intermediate pigments form a high-energy bridge, the site energies of which are stabilized by a particularly large number (>100) of amino acid residues. The concentration of low energy exciton states in the antenna is larger on the side of the A-branch of the reaction center, implying an asymmetric delivery of excitation energy to the latter. This asymmetry in light-harvesting may provide the key for understanding the asymmetric use of the two branches in primary electron transfer reactions. Experiments are suggested to check for this possibility.

Original languageEnglish
Pages (from-to)3331-3343
Number of pages13
JournalJournal of the American Chemical Society
Volume132
Issue number10
DOIs
Publication statusPublished - 17 Mar 2010
Externally publishedYes

Fingerprint

Static Electricity
Pigments
Dichroism
Photosystem I Protein Complex
Light
Amino Acids
Excitons
Amino acids
Circular Dichroism
Antennas
Excitation energy
Chlorophyll
Electrons
Coulomb interactions
Electrostatics
Crystal structure
Proteins
LDS 751
Experiments
chlorophyll a

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Structure-based calculations of optical spectra of photosystem i suggest an asymmetric light-harvesting process. / Adolphs, Julian; Müh, Frank; Madjet, Mohamed; Am Busch, Marcel Schmidt; Renger, Thomas.

In: Journal of the American Chemical Society, Vol. 132, No. 10, 17.03.2010, p. 3331-3343.

Research output: Contribution to journalArticle

Adolphs, Julian ; Müh, Frank ; Madjet, Mohamed ; Am Busch, Marcel Schmidt ; Renger, Thomas. / Structure-based calculations of optical spectra of photosystem i suggest an asymmetric light-harvesting process. In: Journal of the American Chemical Society. 2010 ; Vol. 132, No. 10. pp. 3331-3343.
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