Conformational switching explains the intrinsic multifunctionality of plant light-harvesting complexes

T.P. Kruger, E. Wientjes, R. Croce, R. van Grondelle

Research output: Contribution to journalArticleAcademicpeer-review

63 Citations (Scopus)

Abstract

The light-harvesting complexes of photosystem I and II (Lhcas and Lhcbs) of plants display a high structural homology and similar pigment content and organization. Yet, the spectroscopic properties of these complexes, and accordingly their functionality, differ substantially. This difference is primarily due to the charge-transfer (CT) character of a chlorophyll dimer in all Lhcas, which mixes with the excitonic states of these complexes, whereas this CT character is generally absent in Lhcbs. By means of single-molecule spectroscopy near room temperature, we demonstrate that the presence or absence of such a CT state in Lhcas and Lhcbs can occasionally be reversed; i.e., these complexes are able to interconvert conformationally to quasi-stable spectral states that resemble the Lhcs of the other photosystem. The high structural similarity of all the Lhca and Lhcb proteins suggests that the stable conformational states that give rise to the mixed CT-excitonic state are similar for all these proteins, and similarly for the conformations that involve no CT state. This indicates that the specific functions related to Lhca and Lhcb complexes are realized by different stable conformations of a single generic protein structure. We propose that this functionality is modulated and controlled by the protein environment.
Original languageEnglish
Pages (from-to)13516-13521
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number33
DOIs
Publication statusPublished - 2011
Externally publishedYes

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Charge transfer
Conformations
Proteins
Photosystem I Protein Complex
Photosystem II Protein Complex
Chlorophyll
Pigments
Dimers
Spectroscopy
Molecules
Temperature

Keywords

  • pigment-pigment interactions
  • energy transfer pathways
  • charge-transfer state
  • single lh2 complexes
  • far-red fluorescence
  • photosystem-i
  • antenna complexes
  • angstrom resolution
  • protein complexes
  • crystal-structure

Cite this

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abstract = "The light-harvesting complexes of photosystem I and II (Lhcas and Lhcbs) of plants display a high structural homology and similar pigment content and organization. Yet, the spectroscopic properties of these complexes, and accordingly their functionality, differ substantially. This difference is primarily due to the charge-transfer (CT) character of a chlorophyll dimer in all Lhcas, which mixes with the excitonic states of these complexes, whereas this CT character is generally absent in Lhcbs. By means of single-molecule spectroscopy near room temperature, we demonstrate that the presence or absence of such a CT state in Lhcas and Lhcbs can occasionally be reversed; i.e., these complexes are able to interconvert conformationally to quasi-stable spectral states that resemble the Lhcs of the other photosystem. The high structural similarity of all the Lhca and Lhcb proteins suggests that the stable conformational states that give rise to the mixed CT-excitonic state are similar for all these proteins, and similarly for the conformations that involve no CT state. This indicates that the specific functions related to Lhca and Lhcb complexes are realized by different stable conformations of a single generic protein structure. We propose that this functionality is modulated and controlled by the protein environment.",
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Conformational switching explains the intrinsic multifunctionality of plant light-harvesting complexes. / Kruger, T.P.; Wientjes, E.; Croce, R.; van Grondelle, R.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 108, No. 33, 2011, p. 13516-13521.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Conformational switching explains the intrinsic multifunctionality of plant light-harvesting complexes

AU - Kruger, T.P.

AU - Wientjes, E.

AU - Croce, R.

AU - van Grondelle, R.

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PY - 2011

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N2 - The light-harvesting complexes of photosystem I and II (Lhcas and Lhcbs) of plants display a high structural homology and similar pigment content and organization. Yet, the spectroscopic properties of these complexes, and accordingly their functionality, differ substantially. This difference is primarily due to the charge-transfer (CT) character of a chlorophyll dimer in all Lhcas, which mixes with the excitonic states of these complexes, whereas this CT character is generally absent in Lhcbs. By means of single-molecule spectroscopy near room temperature, we demonstrate that the presence or absence of such a CT state in Lhcas and Lhcbs can occasionally be reversed; i.e., these complexes are able to interconvert conformationally to quasi-stable spectral states that resemble the Lhcs of the other photosystem. The high structural similarity of all the Lhca and Lhcb proteins suggests that the stable conformational states that give rise to the mixed CT-excitonic state are similar for all these proteins, and similarly for the conformations that involve no CT state. This indicates that the specific functions related to Lhca and Lhcb complexes are realized by different stable conformations of a single generic protein structure. We propose that this functionality is modulated and controlled by the protein environment.

AB - The light-harvesting complexes of photosystem I and II (Lhcas and Lhcbs) of plants display a high structural homology and similar pigment content and organization. Yet, the spectroscopic properties of these complexes, and accordingly their functionality, differ substantially. This difference is primarily due to the charge-transfer (CT) character of a chlorophyll dimer in all Lhcas, which mixes with the excitonic states of these complexes, whereas this CT character is generally absent in Lhcbs. By means of single-molecule spectroscopy near room temperature, we demonstrate that the presence or absence of such a CT state in Lhcas and Lhcbs can occasionally be reversed; i.e., these complexes are able to interconvert conformationally to quasi-stable spectral states that resemble the Lhcs of the other photosystem. The high structural similarity of all the Lhca and Lhcb proteins suggests that the stable conformational states that give rise to the mixed CT-excitonic state are similar for all these proteins, and similarly for the conformations that involve no CT state. This indicates that the specific functions related to Lhca and Lhcb complexes are realized by different stable conformations of a single generic protein structure. We propose that this functionality is modulated and controlled by the protein environment.

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KW - single lh2 complexes

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KW - photosystem-i

KW - antenna complexes

KW - angstrom resolution

KW - protein complexes

KW - crystal-structure

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DO - 10.1073/pnas.1105411108

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