1. The First Events Of Photosynthesis. The Design Of A BioSolar Cell
Rienk van Grondelle

2. Photosynthesis Stores About 8x The Total World’s Energy Need

3. Waar vindt de fotosynthese plaats?

4. The Photosynthetic Membrane

5. Top-view of the Photosystem II-LHCII supercomplex

6. Peripheral Light-Harvesting Complex II of Plants.
Binds 50% of all Chlorophyll on this planet

7. From Photosynthesis to Artificial Photosynthesis
The major design principles of photosynthesis

8. 1. Excitons
The effective energy storage in antenna complexes is possible due to the presence of light-harvesting pigments (chlorophylls, carotenoids, bilins) with long-lived excited states and a high cross-section for light absorption.
The elementary excitation of the antenna is described by the wavefuction n, which correspond to excitation of the n-th pigment. Quantum mechanics dictates that when neighbouring pigments are coupled because they are closeby, the excited state of the complex is given by a superposition of such wavefunctions, i.e. c1n1+c2n2+…, where one elementary excitation is shared between a number of molecules.
Such a collective excitation (denoted ‘exciton’) is different from independently excited molecules n1, n2,… due to correlations (‘coherences’) between them given by c1*c2…… Such coherences can be produced if the electronic Hamiltonian contains off-diagonal terms, i.e. Hn2n1. In this coherent state one molecule ‘knows’ about the excitation of its neighbours.
This dramatically changes the spectrum of a pigment aggregate as well as the energy transfer dynamics. In natural antenna complexes these features produce more efficient light absorption, faster conversion from short- to long-wavelength spectral bands, and increase the irreversible trapping of excitations by the RC.

9. Transfer rates between two Chl molecules (as a function of the energy gap and interaction energy between them) calculated according to modified Redfield (A) and Förster (B) expressions.
The specific non-monotonous dependence of the rates on the energy gap and interaction energy is determined by the shape of exciton-phonon spectral density for Chl.

10. Relaxation in the Exciton Manifold of LH2
Relaxation between one-exciton states (k,r) and (p,s), where kr and ps for coherence transfer or decay, or k=r and p=s for population transfer, is given by the term nmcnkcnpcmrcmsJkp<vnvm>.
Bottleneck
k-th exciton state

12. 4 nm Peripheral Light-Harvesting Complex II of Plants.
Binds 50% of all Chlorophyll on this planet
4 nm

14. Energy Transfer in PE545; a peripheral light-harvesting complex from cryptophyte algae

15. From Photosynthesis to Artificial Photosynthesis
The major design principles of photosynthesis

16. 2. Quantum Coherence

17. From Photosynthesis to Artificial Photosynthesis
The major design principles of photosynthesis

18. 3. High pigment/protein ratio: ultrafast (< 1 ps) energy transfer
Mg-Mg-distance about 1 nm
Couplings of cm-1
20 ps trapping time
>30% of the mass is pigment!!!!
Plant PSI

19. From Photosynthesis to Artificial Photosynthesis
The major design principles of photosynthesis

20. 4. Long exciton lifetimes when the Reaction Center is absent or no ‘concentration quenching’.
Antenna
lifetime
LH1
~1 ns
LH2
CP47
~4 ns
LHC II
~2 ns
Chlorosome
~200 ps
Chl a aggregates
< 20 ps
Stark ++
+++ ??

21. From Photosynthesis to Artificial Photosynthesis
The major design principles of photosynthesis

22. 5. The Supra Molecular Organization
20 nm
2004
1950’s 22

23. Architecture and constituents of a spherical chromatophore vesicle from R. sphaeroides constructed from AFM/LD data (37, 39)
Architecture and constituents of a spherical chromatophore vesicle from R. sphaeroides constructed from AFM/LD data (37, 39). (a) Light-harvesting complexes, LH2 (green) and LH1 (red), absorb light and transfer the resulting excitation to the RC (blue), which subsequently initiates electron transfers reducing quinone to hydroquinone (not shown); the bc1 complex (yellow) oxidizes hydroquinone to create a proton gradient across the membrane, which in turn is used by ATP synthase (orange) for ATP production. Electrons are shuttled back to the RC by cytochrome c2 (not shown). The current study focuses solely on the light-harvesting process within the vesicle, and accordingly, bc1 complexes and ATP synthase are not considered, being depicted schematically peripheral to the chromatophore, although other bc1 complexes may be located within the vesicle closer to the RC–LH1–PufX complexes. The ratio of surface area covered by RC-LH1 versus LH2 complexes is 1:1.31 for the first vesicle (shown) and 1:3.23 for the second vesicle (Fig. 2 d and f). (b) BChls (represented by their porphyrin rings) of the atomic model for the RC-LH1 complex constructed for this study based on cryo-EM data (24). The PufX polypeptide is not included. (c) BChls of the LH2 complex based on R. acidophila (23). AFM images (d) (37) are used to identify the arrangement of pigment–protein complexes within planar patches (e). An area-preserving map from the plane on to the sphere, the inverse-Mollweide projection (89) (Eq. 1), is then used to position pigment–protein complexes on the vesicle surface (f). To minimize distortions, multiple planar patches were used, whose sizes are small compared with the inner diameter of the reconstructed vesicle (60 nm). [a–c were made with the program VMD (Visual Molecular Dynamics) (90).]
Şener M. K. et.al. PNAS 2007;104:
©2007 by National Academy of Sciences

25. From Photosynthesis to Artificial Photosynthesis
The major design principles of photosynthesis

26. 6. Multiple Pathways for Energy Transfer and Many Entries into the Reaction Center
Chls at 3-4 nm transfer excitations in ~10 ps!!!

27. The RC-LH gap: Förster vs. Marcus* e-
Chlorophylls at 3-4 nm transfer excitations into the RC in ~ 10 ps.
And electrons out of the RC in ~1 second!!!!!!

28. From Photosynthesis to Artificial Photosynthesis
The major design principles of photosynthesis

29. 7. Multiple Pathways for Light-Driven Charge Separation

30. In The Bacterial RC Charge Separation Originates From The Special Pair
3 ps
1 ps
Zinth cs.

31. In RCs of green plants
There is NO special pair

33. Experimental Evidence For Two Paths in the PS2 RC
Romero et al,submitted

34. Pigments in The Active Branch of the RC
Scherz et al, 2010

35. From Photosynthesis to Artificial Photosynthesis
The major design principles of photosynthesis

36. 8. Photoprotection in LHCII
3Chl-> 3Car
Peterman et al, 1995

37. Non-Photochemical Quenching
To Regulate The Energy Flow The Light-Harvesting Antenna Has The Ability To Switch Off!!!
Non-Photochemical Quenching
DCMU
1 min P AL Fo Fm
Fm’
NPQ
Fluorescence Yield
Time

38. Target Analysis With a Real Annihilation Model
Lhc2 quenching:
Target Analysis With a Real Annihilation Model
Chl 1
Chl 2
Car T kQ kT kR
Annihilation Q k1 γ K
Car*

39. Is LHCII a Switch??????
Chl a
Lut1 Qy S1
NPQ
a611
a612
a610
Neo A B

41. Principles Excitons\ Quantum Coherence Concentration
Spatial Organization
Supramolecular Organization
Multiple entries to catalytic center
Multiple ET pathways
Photoprotection

42. Acknowledgements
Vladimir Novoderezhkin, Alexander Doust, Jan Dekker, Chantal van der Weij-de Wit, Ivo van Stokkum, Bruno Robert, Alessandro Marin, Tjaart Krueger, Natalia Pawlowicz, Sandrine d’Haene, Henny van Roon, Maxime Alexandre, Thomas Cohen Stuart, Cosimo Bonetti, Rudi Berera, John Kennis, Neil Hunter, Marcus Wendling, Eli Romero, Christian Ilioalia, Mariangela DiDonato, Manolis Papagiannakis, Mikas Vengris, Delmar Larson, Herbert van Amerongen, Marloes Groot, Miguel Palacios, Raoul Frese, Greg Scholes, Roberta Croce, Andy Stahl, Graham Fleming, Leonas Valkunas, Andy Pascal, Lavanya Premvardhan, Gert van der Zwan, Sacha Ruban, Peter Horton, Jos Thieme, etc etc