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

为了分析基于发色团高能量跃迁的生物材料结构，利用广岛大学同步辐射中心（HSRC）的同步辐射源（HiSOR），构建了真空-紫外圆二色分光光度计（VUVCD），该分光光度计能够在高真空溶液中测量310 ~ 140 nm波长区域的CD光谱。通过更换单色仪中的光栅反射镜，提高了光谱的信噪比。通过对d-樟脑-10-磺酸铵CD光谱的监测，证实了所构建体系的性能令人满意。8种氨基酸的VUVCD光谱已发表在《化学快报》2002年第826期。此外，我们用珀尔帖热电元件构建了样品池的温度控制单元，使样品保持在-30至70℃的温度范围内。该系统被用于研究肌红蛋白的冷变性，该系统的性能发表在分析科学19,129（2003）。对各种糖和蛋白质的VUVCD光谱的测量和理论赋值进一步证实了所构建的分光光度计的实用性。该VUVCD分光光度计将于2003年4月正式投入使用。

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.