Mr. Leonid Rapatskiy

 

 

 

 

 

 

 

Dr. Leonid Rapatskiy

Lubitz Group
MPI for Bioinorganic Chemistry
Max-Planck-Gesellschaft
Stiftstrasse, 34 - 36
Floor/Room: L. 01, room 445
45470 Mülheim a. d. R
Phone +49208-306-3651
Fax +49208-3063951

Mini Academic CV

University degrees:

First degree or intermediate examination:

  • BSc in Physics, 2005, Novosibirsk State University, city of Novosibirsk, Russia

Second degree and/or intermediate examination:

  • MSc in Physics, 2007, Novosibirsk State University, city of Novosibirsk, Russia

Publications:

  • L. Rapatskiy, V. Khlestkin, T. Duda, L. Sveshnikova, O. Semenova, S. Dzuba, (2006), CW EPR Study of the Molecular Dynamics of Nitronyl Nitroxide on LB Films // Proceedings of X International Youth Scientific School Actual Problems of Magnetic Resonance and Its Application, Kazan, Russia.
  • Ivanova N. A., Onischuk A. A., Vosel S. V., Purtov P. A., Kulik L. V., Rapatskiy L. L., Vasenin N. T., Anufrienko V. F., (2009), EPR spectra of aerosol particles formed by pyrolysis of C3H8 plus Ar and C3H8 plus Fe(CO)5 plus Ar mixtures in a flow reactor, Appl. Magn. Res., 35, 625-637.
  • Kulik L. V., Rapatsky L. L., Pivtsov A. V., Surovtsev N. V., Adichtchev S. V., Grigor'ev I. A., Dzuba S. A., (2009), Electron-nuclear double resonance study of molecular librations of nitroxides in molecular glasses: quantum effects at low temperatures, comparison with low-frequency Raman scattering, J Chem Phys., 131.6, 064505.

Attended conferences:

  • Solar-H2 European Project Meeting, 2009, Tarragona, Spain, poster.
  • 18th Photosynthese-Workshop Nord-West, 2009, Potsdam, Germany, poster.

Prices/Scholarships:

  • 2008 DAAD scholarship for foreigner students

BioStruct PhD project

Pulse EPR study of substrate water binding to the Oxygen-Evolving Complex in PSII and in model Mn-complexes
Aim of the project is characterization of the mode of substrate water binding to the Oxygen Evolving Complex in Photosystem II and model Mn-complexes by advanced pulse EPR methods. Photosynthesis involves a complicated network consisting of many light- and dark-reactions. The light-trapped steps occur in the large pigment-protein complexes called photosystems. In green plants and algae, two different photosystems (PSI and PS II) are working in series to utilize the light energy to drive the water splitting electron- and proton-transfers. This process is well known as the Z-scheme. At the luminal side of the thylakoid membrane, PSII harbors a special inorganic complex comprising four manganese ions and one calcium ion (Mn4OxCa cluster, x means that the oxygen number is not known exactly but x>4), where two substrate waters are oxidized and the molecular oxygen is formed. During this procedure Mn4OxCa undergoes a so called S-state cycle consisting of five distinctive paramagnetic intermediates (Si, i=0-4). The successive light-induced charge separation in P680 (a special chlorophyll pigment in PSII) advances continuously the S-states. Up to date, the geometric and electronic structure of the Mn4OxCa cluster is still ambiguous. Furthermore, the binding side(s) and mode(s) of the substrate water are not unveiled since water is also the solvent for the other biological activities. Revealing of these questions is an urgent project, as the shortage of energy becomes inevitable. Provided that the mechanism of the natural light-induced water splitting is elucidated, this could be used to solve the energy problem and help the human society. Experimental techniques based on electron paramagnetic resonance (EPR) spectroscopy are powerful to probe the binding side(s) and mode(s) of the substrate water in the Mn4OxCa cluster during the S-state cycle of PSII. For example, the used pulse EPR are: ESE (electron spin echo), ESEEM (electron spin echo envelope modulation) and ENDOR (electron-nuclear double resonance) and HYSCORE (Hyperfine Sublevel CORRElation). Such methods work best when they are combined with isotope labeling, which allows addressing specific atoms. The 2H- 17O-labeling can be used with the above mentioned techniques to probe substrate water binding, since they carry a nuclear spin that can interact with the electron spin of the paramagnetic states of the OEC (Oxygen-Evolving Complex). Also, ENDOR is used to reveal the electronic structure of the Mn4OxCa cluster, which is indispensable to locate the substrate water(s). To ensure high reliability of the interpretation of the experimental results, the measurements will be carried out using multifrequency approach. The pulse EPR spectrometers operating at X- (9.5 GHz) and Q-band (34 GHz) frequencies will be employed. The specific goals of the project are: 1. Pulse 17O-HYSCORE measurements on the 2H- 17O-labeled Mn(II)Mn(III) and Mn(III)Mn(IV) complexes. 2. Interpretation of the results of pulse EPR and ENDOR experiments by means of numerical simulation of the obtained spectra. 3. Pulse EPR study of 2H- 17O-substrate labeled S0-state of the OEC. At present such data exist only for the S2-state of the OEC.

Supervisors

Topic Supervisor:

undefinedProf. Dr. Wolfgang Lubitz, MPI for Bioinorganic Chemistry, Max-Planck-Gesellschaft Mülheim a. d. R., Lubitz Grouprsität Düsseldorf, Schmitt Group

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