Objective
Photosynthesis is a fundamental and a most important process on Earth on which almost all living organisms depend. In the past decades of the century, an essential progress has been achieved in understanding of the processes occurring in the photosynthetic apparatus of bacteria, algae and plants. The process includes the following: light quantum energy is absorbed by specialized structures - the antenna complexes which consume the quants and transform their energy into that of electronic excitation, transfer of the energy from antenna to the reaction centres where it is transformed into the energy of separate charges.
The photosynthetic bacteria possess relatively simple photosystmes, therefore they are very attractive models for studies of both the processes of light energy transformation into the chemical free energy and the structures providing for efficiency of these processes. An important stage providing for a breakthrough in this field was the crystallization and the following X-ray analysis of the reaction centres and light-harvesting antenna complexes from the purple non-sulfur photosynthetic bacteria. For the first time could the atomic structure of the complexes be seen and the position of the photosynthesis co-factors (pigments) be related to the functions of the complexes. Directed mutagenesis of genes encoding structural subunits of antenna complexes, in combination with various forms of spectroscopy (RR, FTIR-RR, SERC, CD) and biochemistry, provides a means of testing structural models of these complexes and of enhancing our understanding of the existing crystallographic data.
The theme of the project is a detailed investigation of the unique peripheral antenna complex from the sulfur bacteria Chromatium minutissimum by means of genetic, spectral and biochemical methods. Two west laboratories are pioneers in the field of site-direct mutagenesis of antenna from non-sulfur bacteria Rb. sphaeroides and investigations of fine changes occuring in pigment clusters during such mutations. In order to extend the fruitful research, collaboration will be initiated with a biochemist and a theoretician, both from Russia, who have pioneered in biochemical studies and theoretical calculations of the native state of pigment clusters in complexes. The expected outcome of the complex investigation of the peripheral antenna will enable us not only to improve our knowledge of the organization of the highly-stable transmembrane complexes, but also to better grasp the role of the pigments in their structure stabilization.
The mollar details of the complexes organization will allow to elaborate artificial biomimetic cells that would be able to convert solar energy on technological scale or to use them for biotechnological goals creating in vivo stable and highly efficient systems for light energy transformation into chemical free energy.
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91191 Gif/Yvette
France