| Co-Investigator(Kenkyū-buntansha) |
MITSUI Toshio Meiji University, Faculty of Science and Engineering, Department of Physics, Pro, 理工学部, 教授 (70000726)
EBASHI Setsuro Okazaki Ational Institutes President, 機構長 (10009863)
IKEGAMI Akira Keio University School of Medicine Professor, 医学部, 教授 (60011483)
IIZUKA Tetsutaro The Institute of Physical and Chemical Research Chief Researcher, 主任研究員 (30029475)
ANDO Masami National Institute of High Physics Photon Factory Professor, 放射光実験施設, 教授 (30013501)
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| Research Abstract |
Recently diffraction and scattering experiments with use of strong X-ray in synchrotron radiation have rapidly developed. The experiments to analyze enzymatic reactions in crystals with high time resolutions have started and dynamic structural analyses on muscle contraction and functions of membrane proteins have become able to analyze. The aims of this research are to combine researchers who are using and interested in synchrotron radiation, to make the present questions on various proteins and dynamic supramolecular structures in biological systems clear and to progress this field. The following topics were reported in this year : The crystal structure analysis sytem for big molecules with Weissenberg camera and an imaging plate was developed and the performance was confirmed to be more efficient than any other equipments in the world by the analysis of the crystal of reverse transcriptase which acts when AIDS virus multiplies. A full automated rapid x-ray diffractometor was develope
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d and the performance was evaluated with use of tetrazolylmyoglobin and mashroom lectin. A focusing type soft x-ray microscope with zoneplates was developed and the availability to biological materials was confirmed by the observation of red blood cells and so on. In the field of crystal strucutres of proteins, the following protein structures were analyzed ; immunogloblin Fv fragments, archaebacterium ferredoxin, cytochrome C3 and c553 of sulfate-reducing bacteria, hydrogenase, high molecular weight cytochrome and so on. The differences in binding charactors between iron and ligand moleculaes were found by analyses on x-ray absorption spectra among oxidized cytochrome P450, peroxidase and myoglobin. The reaction scheme of dissociation of ATP synthetase alpha_3beta_3 into alphabeta was analyzed by measurements of time-dependent small angle x-ray scattering. It was reported that disorder was induced in purple membrane during photocyle, but the time-dependent diffraction change showed no disorder during photocycle. The function mechanism of oncogene prodeuct rasp21 was analyzed with structural change depending on GTP・GDP exchange reaction. In the field of muscle research, the following phenomena were analyzed ; structural changes of thin filaments during contraction, fine structural changes of actin-myosin systems, and effects of chemical modification of myosin head on the functions. The more precise model of structual change in microvilli of squid visual cells was constructed. Less
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