Dynamics of nanostructural organization and activity of photosynthetic systems in natural and model membranes


dr hab. Květoslava Burda prof. AGH, Faculty of Physics and Applied Computer Science, Department of Bio- and Medical Physics (mail)


Agnieszka Hałas (WFiIS AGH)


Dynamics of nanostructural organization and activity of photosynthetic systems in natural and model membranes

Foreign partner:

Prof. Pierre Sebban, Laboratoire de Chimie Physique, Faculté de'Orsay, UMR CNRS 8000, Université de Paris Sud IX, Bâtiment 349, 91405 Orsay cedex France
Prof. Ralph Bock, dr Mark A. Schoettler, Department III – Organelle Biology and Biotechnology, Max Planck Institute of Molecular Plant Physiology Wissenschaftspark Golm, Am Mühlenberg 1, D-14476 Potsdam, Germany

Brief description:

Photosynthesis is a process of conversion of light energy into chemical energy taking place in plant chloroplasts and in cells of photosynthetic prokaryotes. Being one of the most important processes in nature, it attracts attention of many researchers as a potential source of commercial energy. One believes that if one better understands photosynthesis on the molecular level, one will be able to construct devices mimicing the photosynthetic processes which would allow for transforming solar energy into electric one using water as the source of electrons and protons (photosystem II from cyanobacteria, algae and higher plants is able to oxidize water).

The aim of the PhD project is to recognize and describe the mechanism responsible for coupling of the electron transfer on the donor and acceptor side of the photosynthetic apparatus. The photoelectron transfer in natural systems, in photosynthetic bacteria and green plants, has a high efficiency because of a phase boundary formed by the photosynthetic membrane and of the existence of a highly organized structure and optimized arrangement of the active redox cofactors. However, an additional activation energy is necessary to sustain the electron and proton transport within the photosynthetic units. This energy is coming from anharmonic (fast collective) atomic fluctuations of the protein-lipid matrix of the system but the way that the subsequent redox active components interact and how the dynamics (flexibility or rigidity) of the photosynthetic enzyme is involved in its redox activity remains unclear.

The PhD student will work on the structure, function and dynamics of bacterial reaction center and photosystem II from higher plants (tobacco).

Our laboratory is in many respects complementary to those of our partners from France and Germany, which will give our students to learn the whole spectrum of experimental techniques under supervision of the best experts in this field and to get acquainted with the methods to produce and analyze mutated systems and use this knowledge to get a better insight into the molecular mechanism of the action of the photosynthetic apparatus. Such an "interdisciplinary" cooperation of physicists, biochemists and biologist will result in modern profile of the PhD studies.

Students international exchange:

Visit of a PhD-student to the Laboratoire de Chimie Physique, Faculté de'Orsay, France:
reporting period 1) III (6 months),
2) reporting period V (6 months);
Studies of the "structure-function" relationship at the electron-proton capabilities of native and genetically modified core proteins of the bacterial reaction centers (RC), applied experimental methods: time resolved absorbance spectrometer triggered by a Yag laser flash (~ 5ns) at 532 nm (or at 355 and 266 nm) with time resolution of 5 µs for monitoring the ET kinetics as well as proton uptake kinetics and stoichiometries by methods of pH sensitive dyes; chromatography with ion exchange or nickel columns for purifying the proteins of wild type and mutated reaction centers.
3) Visit of a PhD-student to the Max Planck Institute of Molecular Plant Physiology Wissenschaftspark Golm, Germany: reporting period VII-VIII (12 months); Characterization of the photosynthetic membranes containing mutated cytochrome b559 using, electrophoresis, dual modulated absorbance and fast fluorescence spectrometer; preparation of wild type and mutated photosystem II (PSII) enriched in isotope 57Fe for dynamical studies of the heme and non-heme iron in PSII.

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