Development of synchrotron-radiation vacuum-ultraviolet circular dichroism spectrophotometer and its application for structural analysis of biomaterials

为了利用发色团的高能跃迁分析生物材料的结构，我们利用广岛大学同步辐射中心（HSRC）的同步辐射光源（希索），构建了真空紫外圆二色性（VUVCD）分光光度计。通过更换单色仪中的光栅镜，提高了光谱的信噪比。通过对d-樟脑-10-磺酸铵的圆二色光谱的监测，证实了所构建体系的性能是令人满意的。八种氨基酸的VUVCD光谱发表在Chemistry Letters，2002，826中。此外，我们还用珀耳帖热电元件构造了样品池的温度控制单元，使样品保持在-30 ~70 ℃的温度范围内。该系统用于研究肌红蛋白的冷变性，并且该系统的性能发表在Analytical Sciences 19，129（2003）中。通过对多种糖和蛋白质的VUVCD光谱的测量和理论归属，进一步证实了所构建的分光光度计的准确性。该VUVCD分光光度计将于2003年4月开放供一般使用。

In order to analyze the structure of biomaterials based on the higher energy transition of chromophores, we constructed the vacuum-ultraviolet circular dichroism (VUVCD) spectrophotometer which is capable of measuring the CD spectra in the wavelength region of 310-140 nm under high vacuum in the solution, using the synchrotron radiation source (HiSOR) at Hiroshima University Synchrotron Radiation Center (HSRC). The signal-to-noise ratio of the spectra was improved by exchanging the grating mirror in the monochromator. The performance of the constructed system was confirmed to be satisfactory by monitoring the CD spectra of ammonium d-camphor-10-sulfonate. The VUVCD spectra of eight amino acids were published in Chemistry Letters, 2002, 826. Further we constructed the temperature control unit of the sample cell with a Peltier thermoelectric element to keep the sample in the temperature range from -30 to 70℃. This system was applied for studying the cold-denaturation of myoglobin and the performance of the system were published in Analytical Sciences 19, 129 (2003). Usefulness of the constructed spectrophotometer was further confirmed from the measurements and theoretical assignment of VUVCD spectra of various sugars and proteins. This VUVCD spectrophotometer will be opened for common utilization from April of 2003.