Electronic coherence lineshapes reveal hidden excitonic correlations in photosynthetic light harvesting

2012 ◽  
Vol 4 (5) ◽  
pp. 396-404 ◽  
Author(s):  
Cathy Y. Wong ◽  
Richard M. Alvey ◽  
Daniel B. Turner ◽  
Krystyna E. Wilk ◽  
Donald A. Bryant ◽  
...  
Keyword(s):  
Light Harvesting ◽  
Electronic Coherence

scholarly journals Electronic coherence lifetimes of the Fenna–Matthews–Olson complex and light harvesting complex II

2019 ◽  
Vol 10 (45) ◽  
pp. 10503-10509 ◽  
Author(s):  
Shawn Irgen-Gioro ◽  
Karthik Gururangan ◽  
Rafael G. Saer ◽  
Robert E. Blankenship ◽  
Elad Harel
Keyword(s):  
Energy Transport ◽  
Light Harvesting ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Efficient Energy ◽  
Naturally Occurring ◽  
Light Harvesting Complex Ii ◽  
Electronic Coherence ◽  
Excitonic States

The study of coherence between excitonic states in naturally occurring photosynthetic systems offers tantalizing prospects for uncovering mechanisms of efficient energy transport.

scholarly journals Disentangling Dynamical Quantum Coherences in the Fenna-Matthews-Olson Complex

2021 ◽  
Author(s):  
Hong-Guang Duan ◽  
Ajay Jha ◽  
Lipeng Chen ◽  
Vandana Tiwari ◽  
Richard Cogdell ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Reaction Center ◽  
Low Temperatures ◽  
Quantum Coherence ◽  
Energy Transport ◽  
Light Harvesting ◽  
Quantum Decoherence ◽  
Strong Temperature Dependence ◽  
Temperature Dependent ◽  
Electronic Coherence

Abstract In the primary step of natural light-harvesting, the energy of a solar photon is captured in antenna chlorophyll as a photoexcited electron-hole pair, or an exciton. Its efficient conversion to stored chemical potential occurs in the special pair reaction center, which has to be reached by down-hill ultrafast excited state energy transport. Key to this process is the degree of interaction between the chlorophyll chromophores that can lead to spatial delocalization and quantum coherence effects. The importance of quantum contributions to energy transport depends on the relative coupling between the chlorophylls in relation to the intensity of the fluctuations and reorganization dynamics of the surrounding protein matrix, or bath. The latter induce uncorrelated modulations of the site energies, resulting in quantum decoherence, and localization of the spatial extent of the exciton. The current consensus is that under physiological conditions quantum decoherence occurs on the 10 fs time scale, and quantum coherence plays little role for the observed picosecond energy transfer dynamics. In this work, we reaffirm this from a different point of view by finding that the true onset of important electronic quantum coherence only occurs at extremely low temperatures of ~20 K. We have directly determined the exciton coherence times using two-dimensional (2D) electronic spectroscopy of the Fenna-Matthew-Olson (FMO) complex over an extensive temperature range. At 20 K, we show that electronic coherences persist out to 200 fs (close to the antenna) and marginally up to 500 fs at the reaction-center side. The electronic coherence is found to decay markedly faster with modest increases in temperature to become irrelevant above 150 K. This temperature dependence also allows disentangling the previously reported long-lived beatings thought to be evidence for electronic quantum coherence contributions. We show that they result from mixing vibrational coherences in the electronic ground state. We also uncover the relevant electronic coherence between excited electronic states and examine the temperature-dependent non-Markovianity of the transfer dynamics to show that the bath involves uncorrelated motions even to low temperatures. The observed temperature dependence allows a clear separation of the fragile electronic coherence from the robust vibrational coherence. The specific details of the critical bath interaction are treated through a theoretical model based on measured bath parameters that reproduces the temperature dependent dynamics. By this, we provide a complete picture of the bath interaction which places these systems in the regime of strong bath coupling. We believe this main conclusion to be generically valid for light harvesting systems. This principle makes the systems robust against otherwise fragile quantum effects as evidenced by the strong temperature dependence. We conclude that nature explicitly exploits decoherence or dissipation in engineering site energies to yield downhill energy gradients to unerringly direct energy, even on the fastest time scales of biological processes.

Vibrational Beatings Conceal Evidence of Electronic Coherence in the FMO Light-Harvesting Complex

2014 ◽  
Vol 118 (45) ◽  
pp. 12865-12872 ◽  
Author(s):  
Roel Tempelaar ◽  
Thomas L. C. Jansen ◽  
Jasper Knoester
Keyword(s):  
Light Harvesting ◽  
Light Harvesting Complex ◽  
Electronic Coherence

scholarly journals Electronic coherence effects in photosynthetic light harvesting

2011 ◽  
Vol 3 (1) ◽  
pp. 211-221 ◽  
Author(s):  
Tzu-Chi Yena ◽  
Yuan-Chung Cheng
Keyword(s):  
Light Harvesting ◽  
Coherence Effects ◽  
Electronic Coherence

High-Resolution electron crystallography of the light-harvesting chlorophyll-a/b protein complex from chloroplast membranes

1990 ◽  
Vol 48 (1) ◽  
pp. 610-610
Author(s):  
Werner Kühlbrandt ◽  
Da Neng Wang ◽  
K.H. Downing
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Chlorophyll A ◽  
Protein Complex ◽  
Structural Integrity ◽  
Light Harvesting ◽  
Lhc Ii ◽  
Diffraction Patterns ◽  
Difference Fourier ◽  
2D Crystals

The light-harvesting chlorophyll-a/b protein complex (LHC-II) is the most abundant membrane protein in the chloroplasts of green plants where it functions as a molecular antenna of solar energy for photosynthesis. We have grown two-dimensional (2d) crystals of the purified, detergent-solubilized LHC-II . The crystals which measured 5 to 10 μm in diameter were stabilized for electron microscopy by washing with a 0.5% solution of tannin. Electron diffraction patterns of untilted 2d crystals cooled to 130 K showed sharp spots to 3.1 Å resolution. Spot-scan images of 2d crystals were recorded at 160 K with the Berkeley microscope . Images of untilted crystals were processed, using the unbending procedure by Henderson et al . A projection map of the complex at 3.7Å resolution was generated from electron diffraction amplitudes and high-resolution phases obtained by image processing .A difference Fourier analysis with the same image phases and electron diffraction amplitudes recorded of frozen, hydrated specimens showed no significant differences in the 3.7Å projection map. Our tannin treatment therefore does not affect the structural integrity of the complex.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

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