Macromolecular Crystallography Research with Synchrotron Radiation

利用由半胱氨酸和甲硫氨酸残基的硫原子或由核酸的磷原子提供的非常小的异常衍射信号（固有地存在于所有蛋白质或RNA/DNA中）可以成功地用于解析蛋白质的晶体结构。这种方法，部分是由我们开创的，目前越来越受欢迎，并成为大分子晶体学实践中的常规技术。使用同步辐射从寡核苷酸和寡肽晶体测量了在0.55-0.7埃范围内的极高分辨率的衍射数据，并且改进的模型揭示了所研究分子的前所未有的结构细节，包括原子之间的σ键处的电子密度。在这种结构中观察到的非常精细的特征将有助于改善用于在较低分辨率下常规细化蛋白质晶体结构的立体化学库。我们参与了几个关于各种生物学重要蛋白质的合作结构项目，如用作生物标志物的荧光蛋白，人类线粒体解旋酶，根瘤菌岩藻糖基转移酶和植物S-腺苷-同型半胱氨酸水解酶。

Utilization of a very small anomalous diffraction signal provided by sulfur atoms of the cysteine and methionine residues or by phosphorus atoms of nucleic acids, intrinsically present in all proteins or RNA/DNA can be successfully used to solve crystal structures of proteins. This approach, in part pioneered by us, is currently gaining increasing popularity and becomes a routine technique in the practice of macromolecular crystallography. The diffraction data to extremely high resolution in the range of 0.55-0.7 angstrom were measured using synchrotron radiation from crystals of oligonucleotides and oligopeptides, and the refined models revealeed the unprecedented structural details of the investigated molecules including electron densities at the sigma bonds between atoms. The observed very fine features in this structures will serve to improve the stereochemical libraries used for routine refinement of protein crystal structures at lower resolution. We participated in several collaborative structural projects on various biologically important proteins, such as fluorescenty proteins used as biomarkers, human mitochindrial helicase, rhizobium fucosyltransferase and plant S-adenosyl-homocysteine hydrolase.