|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1993 : ¥200,000 (Direct Cost : ¥200,000)
Fiscal Year 1992 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1991 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Mechanism and velocity measurement of the formation process of plant viruses, tobacco mosaic virus(TMV) and cucumber green mottle mosaic virus(CGMMV), from their constituent RNAs and coat proteins were studied using X-ray beam radiated by synchrotron ring. The aim of the study is, by making the rapid time resolved small-angle X-ray scattering(SAXS) measurements, to elucidate mechanism of the formation of the virus particles from the viewpoint of structural kinetics. Time dependence of the formation of the TMVP particle owing to the entropy driven assembly was observed by the technique of time resolved X-ray small-angle scattering combined with temperature jump method. Ionic strength jump measurements by stopped flow equipment was also performed. From the analysis of the scattering data, radii of gyration and molecular weight of each time frame, thus time dependence of the particie size and shape, during particle formation were determined. Further equiliobrium constants and kinetic parameters of particle formation and degradation under deferent conditions were obtained by the kinetic analysis of the structural parameters obtained.
Scattering measurements combined with the low temperature quenching technique were performed for the observation of the particle formation of the TMV.Solutions under reconstitution process at 20ﾟC, for example, were taken out at 0, 1, 2, ..........., 30 minutes after mixing the RNA and TMVP.Each solution was then cooled down to 5ﾟC immediately to arrest the growing reaction of the virus particie. X-ray scattering measurements of the solutions obtained were done at 5ﾟC.Comparison of the experimental results analyzed by Kratky plots and simulation calculation of Glatter's multy body model reached to a conclusion that the formation of the virus particle is accompanied by the increse of the hight of the first peak and the completion of the virus particle formation is attained by the elongation of the viral rod.