Structure-based simulation of linear optical spectra of the CP43 core antenna of photosystem II

Frank Müh, Mohamed Madjet, Thomas Renger

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

The linear optical spectra (absorbance, linear dichroism, circular dichroism, fluorescence) of the CP43 (PsbC) antenna of the photosystem II core complex (PSIIcc) pertaining to the S0 → S1 (Q Y) transitions of the chlorophyll (Chl) a pigments are simulated by applying a combined quantum chemical/electrostatic method to obtain excitonic couplings and local transition energies (site energies) on the basis of the 2.9 Å resolution crystal structure (Guskov et al., Nat Struct Mol Biol 16:334-342, 2009). The electrostatic calculations identify three Chls with low site energies (Chls 35, 37, and 45 in the nomenclature of Loll et al. (Nature 438:1040-1044, 2005). A refined simulation of experimental spectra of isolated CP43 suggests a modified set of site energies within 143 cm-1 of the directly calculated values (root mean square deviation: 80 cm-1). In the refined set, energy sinks are at Chls 37, 43, and 45 in agreement with earlier fitting results (Raszewski and Renger, J Am Chem Soc 130:4431-4446, 2008). The present structure-based simulations reveal that a large part of the redshift of Chl 37 is due to a digalactosyldiacylglycerol lipid. This finding suggests a new role for lipids in PSIIcc, namely the tuning of optical spectra and the creation of an excitation energy funnel towards the reaction center. The analysis of electrostatic pigment-protein interactions is used to identify amino acid residues that are of potential interest for an experimental approach to an assignment of site energies and energy sinks by site-directed mutagenesis.

Original languageEnglish
Pages (from-to)87-101
Number of pages15
JournalPhotosynthesis Research
Volume111
Issue number1-2
DOIs
Publication statusPublished - 1 Mar 2012
Externally publishedYes

Fingerprint

Photosystem II Protein Complex
Static Electricity
antennae
photosystem II
Electrostatics
Antennas
Pigments
energy
Lipids
Mutagenesis
Excitation energy
Dichroism
Chlorophyll
Terminology
Circular Dichroism
Site-Directed Mutagenesis
Tuning
Crystal structure
Fluorescence
Amino Acids

Keywords

  • Chlorophyll
  • Electrostatic interaction
  • Excitation energy transfer
  • Lipids
  • Mutagenesis
  • Optical spectra

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology
  • Biochemistry

Cite this

Structure-based simulation of linear optical spectra of the CP43 core antenna of photosystem II. / Müh, Frank; Madjet, Mohamed; Renger, Thomas.

In: Photosynthesis Research, Vol. 111, No. 1-2, 01.03.2012, p. 87-101.

Research output: Contribution to journalArticle

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