tailieunhanh - Báo cáo khoa học: Metabolism and Energetics

Biological nitrogen fixation is a vital process in the global nitrogen cycle, transforming dinitrogen in the atmosphere into ammonia. Being a very energy-demanding and oxygen-sensitive process, both expression and activity of the nitrogenase enzyme are tightly regu-lated. Rhodospirillum rubrumis a free-living, photosynthetic, purple non-sulfur nitrogen-fixing bacterium, which has been extensively used as a model organism for metabolic and regulatory studies regarding nitrogen fixation. | Metabolism and Energetics Abstracts Metabolism and Energetics D1-1 Proteomic profiling of Rhodospirillum rubrum under different nitrogen conditions T. T. Selao S. Nordlund and A. Norcn Department of Biochemistry and Biophysics Stockholm University Stockholm SWEDEN Biological nitrogen fixation is a vital process in the global nitrogen cycle transforming dinitrogen in the atmosphere into ammonia. Being a very energy-demanding and oxygen-sensitive process both expression and activity of the nitrogenase enzyme are tightly regulated. Rhodospirillum rubrum is a free-living photosynthetic purple non-sulfur nitrogen-fixing bacterium which has been extensively used as a model organism for metabolic and regulatory studies regarding nitrogen fixation. In order to understand the metabolic effects when changing between different nitrogen sources we have studied both the soluble and the chromatophore membrane-associated proteome of R. rubrum. Using a combination of electrophoretic techniques and mass spectrometry analysis the differential expression and cellular localization of several proteins were studied in relation to nitrogen fixing non-nitrogen fixing and nif-gene derepressing conditions. Acknowledgement This work was supported by grants from the Carl Tryggers Foundation to AN from the Swedish Research Council to SN and from Fundacao para a Ciencia e a Tecnologia FCT - Portugal through the PhD fellowship SFRH BD 23183 2005 to TTS. D1-3 De novo biosynthesis of vitamin B6 - Complex formation of the heteromeric Bacillus subtilis PLP synthase M. Neuwirth S. Wallner K. Flicker and P. Macheroux Graz University of Technology Graz AUSTRIA Pyridoxal-5-phosphate PLP the biologically active form of vitamin B6 serves as an essential cofactor in many enzymatic reactions. In plants fungi archaea protozoa and some eubacteria its de novo biosynthesis is accomplished via a recently discovered pathway different to the well-studied pathway of Escherichia coli. This major pathway leads to .