The Influence of Symmetry on the Electronic Structure of the Photosynthetic Pigment-Protein Complexes from Purple Bacteria

2009 ◽  
pp. 513-533
Author(s):  
Martin F. Richter ◽  
Jürgen Baier ◽  
Richard J. Cogdell ◽  
Silke Oellerich ◽  
Jürgen Köhler
Keyword(s):  
Electronic Structure ◽  
Protein Complexes ◽  
Purple Bacteria ◽  
Photosynthetic Pigment ◽  
Pigment Protein Complexes

scholarly journals Contribution of low-temperature single-molecule techniques to structural issues of pigment–protein complexes from photosynthetic purple bacteria

2018 ◽  
Vol 15 (138) ◽  
pp. 20170680 ◽  
Author(s):  
Alexander Löhner ◽  
Richard Cogdell ◽  
Jürgen Köhler
Keyword(s):  
Low Temperature ◽  
Single Molecule ◽  
Degrees Of Freedom ◽  
Protein Complexes ◽  
Purple Bacteria ◽  
Structural Models ◽  
Spectral Features ◽  
Light Harvesting Complexes ◽  
Pigment Protein Complexes ◽  
Photosynthetic Purple Bacteria

As the electronic energies of the chromophores in a pigment–protein complex are imposed by the geometrical structure of the protein, this allows the spectral information obtained to be compared with predictions derived from structural models. Thereby, the single-molecule approach is particularly suited for the elucidation of specific, distinctive spectral features that are key for a particular model structure, and that would not be observable in ensemble-averaged spectra due to the heterogeneity of the biological objects. In this concise review, we illustrate with the example of the light-harvesting complexes from photosynthetic purple bacteria how results from low-temperature single-molecule spectroscopy can be used to discriminate between different structural models. Thereby the low-temperature approach provides two advantages: (i) owing to the negligible photobleaching, very long observation times become possible, and more importantly, (ii) at cryogenic temperatures, vibrational degrees of freedom are frozen out, leading to sharper spectral features and in turn to better resolved spectra.

Two-photon excitation spectroscopy of photosynthetic light-harvesting complexes and pigments

2019 ◽  
Vol 216 ◽  
pp. 494-506 ◽  
Author(s):  
Alexander Betke ◽  
Heiko Lokstein
Keyword(s):  
Spectral Region ◽  
Protein Complexes ◽  
Photosynthetic Pigment ◽  
Photon Absorption ◽  
Light Harvesting Complexes ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Photon Excitation ◽  
Pigment Protein Complexes ◽  
Two Photon Excitation

Two-photon excitation (TPE) profiles of LHCII samples containing different xanthophyll complements were measured in the presumed 11Ag− → 21Ag− (S0 → S1) transition region of xanthophylls. Additionally, TPE profiles of Chls a and b in solution and of WSCP, which does not contain carotenoids, were measured. The results indicate that direct two-photon absorption by Chls in the presumed S0 → S1 transition spectral region of carotenoids is dominant over that of carotenoids, with negligible contributions of the latter. These results suggest the re-evaluation of previously published TPE data obtained with photosynthetic pigment–protein complexes containing (B)Chls and carotenoids.

Redox Conditions Affect Ultrafast Exciton Transport in Photosynthetic Pigment–Protein Complexes

2017 ◽  
Vol 9 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Marco A. Allodi ◽  
John P. Otto ◽  
Sara H. Sohail ◽  
Rafael G. Saer ◽  
Ryan E. Wood ◽  
...  
Keyword(s):  
Protein Complexes ◽  
Photosynthetic Pigment ◽  
Redox Conditions ◽  
Exciton Transport ◽  
Pigment Protein Complexes
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