Single Molecule Spectroscopy of Pigment Protein Complexes from Purple Bacteria

2007 ◽  
pp. 309-321 ◽  
Author(s):  
Jürgen Köhler ◽  
Thijs J. Aartsma
Keyword(s):  
Single Molecule ◽  
Protein Complexes ◽  
Purple Bacteria ◽  
Single Molecule Spectroscopy ◽  
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.

Exciton Self Trapping in Photosynthetic Pigment–Protein Complexes Studied by Single-Molecule Spectroscopy

2012 ◽  
Vol 116 (36) ◽  
pp. 11017-11023 ◽  
Author(s):  
Ralf Kunz ◽  
Kõu Timpmann ◽  
June Southall ◽  
Richard J. Cogdell ◽  
Arvi Freiberg ◽  
...  
Keyword(s):  
Single Molecule ◽  
Protein Complexes ◽  
Photosynthetic Pigment ◽  
Single Molecule Spectroscopy ◽  
Self Trapping ◽  
Pigment Protein Complexes

Single-Molecule Spectroscopy on Photosystem I Pigment−Protein Complexes

2000 ◽  
Vol 104 (34) ◽  
pp. 8093-8096 ◽  
Author(s):  
F. Jelezko ◽  
C. Tietz ◽  
U. Gerken ◽  
J. Wrachtrup ◽  
R. Bittl
Keyword(s):  
Photosystem I ◽  
Single Molecule ◽  
Protein Complexes ◽  
Single Molecule Spectroscopy ◽  
Pigment Protein Complexes

Single molecule spectroscopy on photosynthetic pigment-protein complexes

2001 ◽  
Vol 91 (3) ◽  
pp. 457-460 ◽  
Author(s):  
F. Jelezko ◽  
C. Tietz ◽  
U. Gerken ◽  
E. Thews ◽  
S. Schuler ◽  
...  
Keyword(s):  
Single Molecule ◽  
Protein Complexes ◽  
Photosynthetic Pigment ◽  
Single Molecule Spectroscopy ◽  
Pigment Protein Complexes

The architecture and function of the light-harvesting apparatus of purple bacteria: from single molecules to in vivo membranes

2006 ◽  
Vol 39 (3) ◽  
pp. 227-324 ◽  
Author(s):  
Richard J. Cogdell ◽  
Andrew Gall ◽  
Jürgen Köhler
Keyword(s):  
Quantum Mechanics ◽  
Energy Transfer ◽  
Single Molecule ◽  
Molecular Mechanisms ◽  
Light Harvesting ◽  
Structural Information ◽  
Purple Bacteria ◽  
Theoretical Background ◽  
Single Molecule Spectroscopy

1. Introduction 2292. Structures 2342.1 The structure of LH2 2342.2 Natural variants of peripheral antenna complexes 2422.3 RC–LH1 complexes 2423. Spectroscopy 2493.1 Steady-state spectroscopy 2493.2 Factors which affect the position of the Qy absorption band of Bchla 2494. Regulation of biosynthesis and assembly 2574.1 Regulation 2574.1.1 Oxygen 2574.1.2 Light 2584.1.2.1 AppA: blue-light-mediated regulation 2594.1.2.2 Bacteriophytochromes 2594.1.3 From the RC to the mature PSU 2614.2 Assembly 2614.2.1 LH1 2624.2.2 LH2 2635. Frenkel excitons 2655.1 General 2655.2 B800 2675.3 B850 2675.4 B850 delocalization 2736. Energy-transfer pathways: experimental results 2746.1 Theoretical background 2746.2 ‘Follow the excitation energy’ 2766.2.1 Bchla→Bchla energy transfer 2776.2.1.1 B800→B800 2776.2.1.2 B800→B850 2786.2.1.3 B850→B850 2796.2.1.4 B850→B875 2806.2.1.5 B875→RC 2806.2.2 Car[harr ]Bchla energy transfer 2817. Single-molecule spectroscopy 2847.1 Introduction to single-molecule spectroscopy 2847.2 Single-molecule spectroscopy on LH2 2857.2.1 Overview 2857.2.2 B800 2867.2.2.1 General 2867.2.2.2 Intra- and intercomplex disorder of site energies 2877.2.2.3 Electron-phonon coupling 2897.2.2.4 B800→B800 energy transfer revisited 2907.2.3 B850 2938. Quantum mechanics and the purple bacteria LH system 2989. Appendix 2999.1 A crash course on quantum mechanics 2999.2 Interacting dimers 30510. Acknowledgements 30611. References 307This review describes the structures of the two major integral membrane pigment complexes, the RC–LH1 ‘core’ and LH2 complexes, which together make up the light-harvesting system present in typical purple photosynthetic bacteria. The antenna complexes serve to absorb incident solar radiation and to transfer it to the reaction centres, where it is used to ‘power’ the photosynthetic redox reaction and ultimately leads to the synthesis of ATP. Our current understanding of the biosynthesis and assembly of the LH and RC complexes is described, with special emphasis on the roles of the newly described bacteriophytochromes. Using both the structural information and that obtained from a wide variety of biophysical techniques, the details of each of the different energy-transfer reactions that occur, between the absorption of a photon and the charge separation in the RC, are described. Special emphasis is given to show how the use of single-molecule spectroscopy has provided a more detailed understanding of the molecular mechanisms involved in the energy-transfer processes. We have tried, with the help of an Appendix, to make the details of the quantum mechanics that are required to appreciate these molecular mechanisms, accessible to mathematically illiterate biologists. The elegance of the purple bacterial light-harvesting system lies in the way in which it has cleverly exploited quantum mechanics.

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