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You searched for +publisher:"Freie Universität Berlin" +contributor:("Prof. Marten Heyn"). One record found.

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Freie Universität Berlin

1. Byrdin, Martin. Measuring and Modeling Excitation Dynamics in Photosystem I.

Degree: 2000, Freie Universität Berlin

In this work, dynamics of excitation energy transfer and decay in a cyanobacterial PS I core antenna-RC-complex from Synechococcus el. is studied combining fluorescence induction techniques with picosecond fluorescence lifetime measurements at temperatures between 5 K and 300 K with special attention to the oxidation state of the primary donor P700. The measured fluorescence behaviour is modeled by simulations of the excited state transfer and decay based on structral and spectral information. For the first time, a difference in the quenching efficiency of the PS I core- antenna-RC-complex with open vs. closed RC was resolved both by fluorescence induction and ps- fluorescence as well as by quasi steady state spectroscopy. As the form of the steady state spectra at RT is (nearly) identical, the found difference of 12┬▒ 5 % in fluorescence yield is not due to spectral differences between the open and closed RC states but to a ~3 ps difference in the overall excitation decay lifetime. Thus, in closed PS I the excited state is quenched slightly worse than in open PS I. Time-resolved fluorescence could resolve non-conservative transfer spectra both at RT and at 5 K, indicating that the quenched state of the complex is not fully equilibrated. As a consequence, trap limitation of the excited state kinetics can be excluded. From the excited state lifetime at 5 K in closed PS I complexes a A720-P700 distance of ~3.5 nm is calculated. The observed inter-monomer exchange of excitation energy suggests the localization of some A720 pigments in the connecting domain of the trimeric unit. Structural/spectral information based simulation of the excited state dynamics reveales the necessiety for some A708 pigments to be placed next to the RC domain to increase the transient population of P700. The kinetics observed on a model with such arrangement of the red pigments yields optimal parameters as an intrinsic charge separation rate constant of (0.5 ps)-1 and a F├Ârster radius of 7.3 nm for the reproduction of the measured fluorescence. Above that, the simulation shows an equilibration pertubation over the whole red wing of the emission and the determining influence of the red pigments. The kinetics in closed PS I can be described by fast quenching via internal conversion if the non-oxidized P700 Chl is set to maximal absorption at 685 nm. Testing the influence of the various parameters leads to the conclusion that for open PS I, the observable excited state decay is characterized by well-balanced kinetics rather than limiting cases. Advisors/Committee Members: n (gender), Prof. Dietmar Stehlik (firstReferee), Prof. Marten Heyn (furtherReferee).

Subjects/Keywords: photosynthesis; time resolved fluorescence; computer simulation; excitation dynamics; photosystem I; 87.15-v; 87.64Aa; 87.64Ni; 31.70Hq; 82.20Rp; 500 Naturwissenschaften und Mathematik::530 Physik::530 Physik

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APA (6th Edition):

Byrdin, M. (2000). Measuring and Modeling Excitation Dynamics in Photosystem I. (Thesis). Freie Universität Berlin. Retrieved from https://refubium.fu-berlin.de/handle/fub188/12094

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Byrdin, Martin. “Measuring and Modeling Excitation Dynamics in Photosystem I.” 2000. Thesis, Freie Universität Berlin. Accessed August 13, 2020. https://refubium.fu-berlin.de/handle/fub188/12094.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Byrdin, Martin. “Measuring and Modeling Excitation Dynamics in Photosystem I.” 2000. Web. 13 Aug 2020.

Vancouver:

Byrdin M. Measuring and Modeling Excitation Dynamics in Photosystem I. [Internet] [Thesis]. Freie Universität Berlin; 2000. [cited 2020 Aug 13]. Available from: https://refubium.fu-berlin.de/handle/fub188/12094.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Byrdin M. Measuring and Modeling Excitation Dynamics in Photosystem I. [Thesis]. Freie Universität Berlin; 2000. Available from: https://refubium.fu-berlin.de/handle/fub188/12094

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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