Photosynthesis 2: Energy conversion and electron conduction in soft matter

1
Photosynthesis 2 Energy conversion and electron
conduction in soft matter
Electron flow in photosynthesis of cyanobacteria
H
ADP
ATP
cytoplasm
Q/QH2/Q
hn
ATPase
bc1
RC
LH-II
LH-I
periplasm
e-
H
cytochrome c2
Electron flow in photosynthesis of purple bacteria
2
Electron flow in photosynthesis of
cyanobacteria and Plants
backward direction respiration food
consumption in mammals
From Nature 411, (2001) 897, W. Kuhlbrandt.
3
Photosynthesis 2 Energy conversion and electron
conduction in soft matter
Electron flow in photosynthesis of cyanobacteria
H
ADP
ATP
cytoplasm
Q/QH2/Q
hn
ATPase
bc1
RC
LH-II
LH-I
periplasm
e-
H
cytochrome c2
Electron flow in photosynthesis of purple bacteria
4
Role of Thermal Disorder on Electron Transfer in
the Photosynthetic Reaction Center
Electron transfer is coupled to the thermal
motion of the surrounding protein.
5
Particle Hole Separation in the Reaction Center
and Solar Cells
protein
protein rotated 900 and stretched
6
Cytochrome c2 docking
H
ADP
ATP
cytoplasm
Q/QH2/Q
hn
ATPase
bc1
RC
LH-II
LH-I
periplasm
e-
H
cytochrome c2
7
Photosynthetic Apparatus of Purple Bacteria
Very Large Conformational Changes
Sergei Izrailev
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Photosynthetic Apparatus of Purple Bacteria
Very Large Conformational Changes
F1
rotatory catalysis (twist conformational change
ATP synthesis )
F1
(from Wang Oster)
elastomechanical
coupling
F0
ATP synthase
energy transformation (proton motive force
rotation)
(Walker, Whilce, Fillingame)
www.ks.uiuc.edu
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Photosynthetic Pathway in Cyanobacteria and Plants
10
Electron Carrying Molecules
bacterio- chlorophyll
chain
bacterio- pheophytin
chain
ubiquinone
chain
11
Particle Hole Separation in the Reaction Center
and Solar Cells
protein
protein rotated 900 and stretched
12
The energy gap is Gaussian distributed
energy gap
energy gap
13
Two State QM System Coupled to Protein Matrix
First case Coupling to a single oscillator
Hamiltonian
Protein matrix is a bath of oscillators
linearly coupled to the electron transfer
according to
only a single oscillator considered at present!
14
Two State QM System Coupled to Protein Matrix
Second case Coupling to an ensemble of
oscillators
Hamiltonian
Protein matrix is a bath of oscillators
linearly coupled to the electron transfer
according to
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Electron Transfer Process Coupled to the Protein
Matrix
Rate for an ensemble of oscillators
Relaxation rate
But we dont know all the coupling constants cj ?
All we need to know is
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Solution of Rate Equation
17
Electron Transfer Process Coupled to the Protein
Matrix
Rate for an ensemble of oscillators
Relaxation rate
But we dont know all the coupling constants cj ?
All we need to know is
18
Electron Transfer Process Coupled to the Protein
Matrix
Relaxation rate
1994
energy gap
energy gap correlation function
rms deviation of energy gap
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Temperature Dependence of Electron Transfer Rate