Download Quantumn Theory of DNA—Approach

Quantum Theory of DNA—
An Approach to Electron Transfer in DNA
H. Sugawara, 2005
Work being done with H. Ikemura
1. Introduction
motivation ⇔ Ikemura Conjecture
Ikemura Conjecture
“Electron transfer in DNA is playing an important role in the information
exchanges among the various sections of DNA.”
Example
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2. Field Theory Technique
Standard technique in particle theory and in condensed matter
theory but maybe not in quantum chemistry.
Consider electrons interacting with the centers of potential (ions)
located at Ri:
electromagnetic interactions (gauge principle)
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◎
electron-phonon interactions
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3. Hartree approximations
Include in V(x) → Veff
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Further approximations
only nearest neighbors
Then we have
Special case of H
→ Su-Schrieffer-Heegger Hamiltonian
→
b, g constant , j longitudinal
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can also be defined in a similar way
Then we replace
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Here
was utilized
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RNA transcription
DNA replication
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◎
Consider classical and longitudinal oscillation
localized (tightly bound) wave function
◎
general case with classical oscillation
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WKB solution
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◎ The
localization depends on the sign of
and of
◎ Back
to the descrete description
applications
(1) Luminescence quenching
(2) Electric current
(3) Absorption of light
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Luminescence quenching
Ru-ligand
mixed
system
luminescence
absorption
Rh
provides electrons ⇒ quenching
quenching occurs by a hole propagation inside DNA
Note
1. Prokariote ・・・ closed string
2. Eukariote ・・・ open string
end: telomere
with certain protein
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Probability of quenching
DNA electrons transfer to (from) metals
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Density at Lh
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Electric current in DNA
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Coupling to backbone electrons
add
This may be important in explaining the current?
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There must be an overlap
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(1) Ef is within the band
(2) Ef is outside of the band
semiconductor-like
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Optical absorption (Sarukura’s proposal)
excited band
ground band
em interaction
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absorption rate
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Conclusion
(1) Three dimensional string action for DNA is derived
(2) Approximate p-electron wave functions are derived
(3) Applications to luminescence quenching, electric current
through DNA and optical absorption are formulated
remaining problems
(1) Comparison with experiments
(2) Bound states with proteins
(3) Quantized phonon
(4) Improvement of approximations
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