X-RAY CRYSTAL AND EXAFS STUDIES OF PS DENTRIFICATIONS AZ

本文报道了PS.天青的X射线晶体结构。一种蓝色的铜 蛋白质，其功能是电子转移，将解决异常 从内在的蛋白质原子分散定相。 同步辐射 提供大约4到80 KeV的X射线， 与适当聚焦的双晶体单色器结合， 收集8.98 KeV的Cu衍射数据和4.00 KeV的S衍射数据 凯 这些强度测量值将与 在8.03 KeV（KuKAlpha发射线），以利用巨大的差异 Cu的Δ f '和Δ f”值增加，S的Δ f”值增加。 在一个能量下的Freidel对的测量与测量相结合 强度的差异作为能量的函数将被用来定位 反常散射体 异常色散相位将用于 与由已知的S和Cu产生的部分结构相结合 位置来计算整个蛋白质的电子密度图。 的 这些定相方法的独特性和普遍性将建立多个 波长衍射作为常规的蛋白质晶体学方法。 EXAFS 对氧化和还原态天青蛋白的研究将平行进行。 水晶实验 EXAFS研究将提供精确的 在氧化和还原状态下的Cu配体的长度 分子。 总之，这些研究将产生结构信息， 1型铜蛋白，这将有助于理解 独特的生化和光谱特性及其功能。

The x-ray crystal structure of azurin from Ps. denitrificans, a blue Cu protein whose function is electron transfer, will be solved by anomalous dispersion phasing from intrinsic protein atoms. Synchrotron radiation which provides x-rays from approximately 4 to 80 KeV will be used in conjunction with a suitably focusing double crystal monochromator to collect Cu diffraction data at 8.98 KeV and S diffraction data at 4.00 KeV. These intensity measurements will be combined with measurements made at 8.03 KeV (the KuKAlpha emission line) to exploit the large differences in Deltaf' and Deltaf" for Cu and the increased value of Deltaf" for S. Measurement of Freidel pairs at one energy in combination with measurement of differences in intensity as a function of energy will be used to locate the anomalous scatterers. The anomalous dispersion phases will be used in conjunction with partial structure phases resulting from the known S and Cu positions to calculate an electron density map of the entire protein. The uniqueness and generality of these phasing methods will establish multiple wavelength diffraction as a routine protein crystallographic method. EXAFS studies on both the oxidized and reduced species of azurin will parallel the crystal experiments. The EXAFS studies will provide precise bond lengths for the Cu ligands in both the oxidized and reduced states fo the molecule. Together, these studies will yield structural information about the Type 1 copper proteins which will facilitate the understanding of the unique biochemical and spectroscopic properties and their function.