Ultraviolet (UV) synchrotron radiation circular dichroism (SRCD) spectroscopy has made an important contribution to the determination and understanding of the structure of bio-molecules. In this paper, we report an innovative approach that we term time-resolved SRCD (tr-SRCD), which overcomes the limitations of current broadband UV SRCD setups. This technique allows accessing ultrafast time scales (down to nanoseconds), previously measurable only by other methods, such as infrared (IR), nuclear magnetic resonance (NMR), fluorescence and absorbance spectroscopies, and small angle X-ray scattering (SAXS). The tr-SRCD setup takes advantage of the natural polarization of the synchrotron radiation emitted by a bending magnet to record broadband UV CD faster than any current SRCD setup, improving the acquisition speed from 10 mHz to 130 Hz and the accessible temporal resolution by several orders of magnitude. We illustrate the new approach by following the isomer concentration changes of an azopeptide after a photoisomerization. This breakthrough in SRCD spectroscopy opens up a wide range of potential applications to the detailed characterization of biological processes, such as protein folding and protein-ligand binding.

中文翻译：

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使用同步加速器自然极化的时间分辨瞬态圆二色光谱。

紫外线（UV）同步辐射圆二色性（SRCD）光谱对确定和理解生物分子的结构做出了重要贡献。在本文中，我们报告了一种称为时间分辨SRCD（tr-SRCD）的创新方法，该方法克服了当前宽带UV SRCD设置的局限性。该技术允许访问超快的时标（低至纳秒），以前只能通过其他方法来测量，例如红外（IR），核磁共振（NMR），荧光和吸收光谱以及小角度X射线散射（SAXS）。tr-SRCD设置利用了弯曲磁体发射的同步加速器辐射的自然极化来比任何当前SRCD设置更快地记录宽带UV CD，将采集速度从10 mHz提高到130 Hz，并将可获得的时间分辨率提高了几个数量级。我们通过跟踪光异构化后偶氮肽的异构体浓度变化来说明新方法。SRCD光谱学的这一突破为生物过程的详细表征（例如蛋白折叠和蛋白-配体结合）打开了广泛的潜在应用领域。