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Effects of distribution of excitation energy transfer times and protein dynamics on spectral hole burning in pigment-protein complexes involved in photosynthesis

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Effects of distribution of excitation energy transfer times and protein dynamics on spectral hole burning in pigment-protein complexes involved in photosynthesis

Herascu, Nicoleta (2013) Effects of distribution of excitation energy transfer times and protein dynamics on spectral hole burning in pigment-protein complexes involved in photosynthesis. PhD thesis, Concordia University.

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Abstract

Understanding the spectral properties of natural photosynthetic complexes (the excited state lifetimes, electron-phonon couplings, distributions of “solvent shifts” of various pigments, and the interactions between them (manifestations of excitonic effects, excitation energy transfer, charge transfer) as well as pigments site energies, lowest-energy states and origin of various emission bands) is fundamental to advance the design of the artificial photosynthetic systems. Traditionally the spectral properties of natural photosynthetic complexes are explored by either time-domain or frequency-domain high-resolution spectroscopy methods, including non-photochemical spectral hole burning (NPHB).
The main goal of this thesis was the study of various effects of the distribution of excitation energy transfer times and protein dynamics on non-photochemical hole burning processes in photosynthetic pigment-protein complexes. In the first part of this

thesis we present our results concerning the inclusion of the distributions of excitation energy transfer (EET) rates (homogeneous line widths) and charge separation rates into
treatment of the resonant and non-resonant NPHB processes in photosynthetic chlorophyll-protein complexes. Thus, the effects of the line width distributions resulting from Förster-type EET between weakly interacting pigments with uncorrelated site distribution functions, on the resonant NPHB process have been explored both theoretically and experimentally in isolated CP43 antenna from spinach. Furthermore, we have also demonstrated that inclusion of the effects of frequency-dependent EET rate distributions and burning following EET on the treatment of non-resonant NPHB spectra of trimeric Fenna-Matthews-Olson protein from Chlorobium tepidum leads to reasonable agreement between the theoretical and experimental data.
The second part of this thesis is focused on the analysis of HB spectral properties of the lowest energy states of Photosystem I (PSI) with the aims to gain better understanding of particular structural origins of these states as well as on the protein dynamics of PSI. We explored the satellite hole structures obtained after illumination at various wavelengths and the dependence of those structures on thermocycling. In order to explore the protein dynamics in PSI SHB experiments and compare it with SPCS observations special attention was devoted to the study of the influence of the P700 redox state on resonant and nonresonant NPHB spectra from cyanobacteria Thermosynechococcus elongatus.

Divisions:Concordia University
Item Type:Thesis (PhD)
Authors:Herascu, Nicoleta
Institution:Concordia University
Degree Name:Ph. D.
Program:Physics
Date:14 September 2013
Thesis Supervisor(s):Zazubovits, Valter
ID Code:977760
Deposited By: NICOLETA HERASCU
Deposited On:13 Jan 2014 16:06
Last Modified:18 Jan 2018 17:45
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