Electron Transfer on the Donor and Acceptor Sides of Photosystem II Explored by Site-Directed Mutagenesis and Kinetic Spectroscopy

Kanazawa, Atsuko

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Description

Title

Electron Transfer on the Donor and Acceptor Sides of Photosystem II Explored by Site-Directed Mutagenesis and Kinetic Spectroscopy

Author(s)

Kanazawa, Atsuko

Issue Date

1997

Doctoral Committee Chair(s)

Crofts, Antony R.

Department of Study

Biophysics and Computational Biology

Discipline

Biophysics and Computational Biology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Biology, Plant Physiology

Language

eng

Abstract

H252Q and six donor-side mutants became the important tools to investigate a new model of neutral tyrosine radical, $\rm Y\sb{Z}\sp\cdot,$ introduced by Gilchrist et al. (1995) and Hoganson et al. (1995). In this new model, $\rm Y\sb{Z}$ is not simply a redox active residue in the electron transfer reactions, but is also directly involved in the water-oxidation. The models are critically-dependent on the presence of a neutral radical form of $\rm Y\sb{Z}\ (Y\sb{Z}\sp{\cdot}).$ The donor-side mutants, $\rm E189 > L,Q,$ and $\rm N191 > A,D,L,$ had only small effects on the pH-dependence of the rate of Q$\rm\sb{A}\sp-$ and oxidized $\rm Y\sb{Z}$ recombination. On the other hand, E189D mutant showed a pH-independent in rate of $\rm Q\sb{A}\sp-$ and oxidized $\rm Y\sb{Z}$ recombination. Based on these data, a simple thermodynamic model was introduced to explain the results and the model of $\rm Y\sb{Z}\sp{\cdot}$ as an oxidized form.

Graduation Semester

1997

Type of Resource

text

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http://hdl.handle.net/2142/85481

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