Research Abstract |
M. Sato setup a sample cell for time-resolved measurement of solution X-ray scattering by modifying a stopped flow mixing cell available commercially as that suitable for time-resolved structural analysis. He also introduced a multi-layer mirror system as a X-ray optics to focus on the incident X-rays at the position of an X-ray detector. The mirror system was quite superior to that using a totally reflected focusing mirror system, which was made use of so far, and realized the incident intensity ten times as bright as that using a totally reflected focusing mirror system. The combination of the X-ray optics with the sample cell establishes an X-ray solution scattering system quite suitable for the time-resolved structural analysis of protein in solution. M. Kataoka developed, as a system for the static structure analysis of protein in solution, the method to analyze the tertiary structure of protein at non-native states and also the heavy-atom replacement method to analyze the reaction
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-intermediate structure of protein. These methods were applied to α-lacatalbumin, bacteriorhodopsin and so on, and shown to be very effective to analyze the protein structure in solution. A new algorithm system to analyze the time-resolved structure of protein in solution was also developed. The algorithm system was then applied to the time-resolved solution scattering data of photo-reaction of purple membrane, and found out the two different structures in the reverse reaction from de-protonized intermediate of Schiff base produced by light absorption. On the other hand, Y. Amemiya developed two typical types of high sensitive CCD-based area detector for real time (automated) measurements and time-resolved measurements of solution X-ray scattering; one is the system in which X-ray image intensifiers are coupled to maximize the detective quantum efficiency for time-resolved measurements, and the other is the system in which tapered optical fibers are coupled for the reduction of the image into the CCD, which is optimized for automated measurements for protein crystallography. Software systems for these CCD-based X-ray detectors to correct image distortion and non-uniformity of response were also developed. Less
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