Time-Resolved X-ray Absorption Spectroscopy on Microsec. Timescales

时间分辨结构测定是试图了解蛋白质反应机制的前沿。X射线吸收光谱(XAS)为研究化学和生物体系中特定原子的环境提供了一个窗口，非常适合于研究生物环境中金属原子的化学。此外，XAS可以应用于广泛的样品相，并可以成功地探索元素周期表中广泛原子的化学环境(从低Z原子，如硫，到重原子，如第三排过渡金属)。我们正在开发一个收集S和更长时间尺度的高质量X射线吸收光谱数据的系统。该方法既可用于全光谱积累，也可用于动力学分光光度。使用这项技术的实验具有巨大的潜力，不仅在研究金属蛋白方面，而且在结合光化学、快速混合和温度跳跃技术观察广泛的化学元素的动态行为方面也具有巨大的潜力。我们通过检测肌红蛋白-一氧化碳复合体在低温下光解后的结构演变来测试该系统。

Time-resolved structure determinations are at the forefront of attempts to understand the mechanisms of protein reactions. X-ray absorption spectroscopy (XAS) provides a window on the environment of specific atoms in chemical and biological systems, and is well suited to examining the chemistry of metal atoms in biological milieu. In addition, XAS can be applied to a wide range of sample phases, and can successfully probe the chemical environment of a wide range of atoms in the periodic table (from low Z atoms, like sulfur, to heavy atoms, like third row transition metals). We are developing a system for collecting high quality x-ray absorption spectroscopy data on s and longer timescales. The method can be used for both full spectra accumulation and kinetic spectrophotometry. Experiments using this technology have vast potential, not only for examining metalloproteins, but also for observing the dynamic behavior of a wide range of chemical elements in conjunciton with photo-chemical, rapid mixing, and temperature jump techniques. We have tested the system by examining the structural evolution of the myoglobin-carbon monoxide complex after photolysis at low temperature.