SELENIUM DERIVATIZATION OF NUCLEIC ACIDS FOR X-RAY CRYSTALLOGRAPHY VIA MAD

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 X射线晶体学是高分辨率测定RNA结构、RNA-蛋白质和DNA-蛋白质复合物结构的有力工具。然而，X射线晶体学中一个长期存在的问题，即用重原子进行衍生化来确定相，在很大程度上减缓了具有新折叠的核酸的结构确定。促进结构测定的一种方法是用共价连接的重原子标记核酸，这使得能够进行相和结构测定。我们开发了一种新的策略，通过用硒取代氧来衍生RNA和DNA，并通过使用MAD定相方法的X射线晶体学证实了这一原理。我们正在通过化学和酶促合成，衍生DNA和具有新折叠的催化和结合RNA序列，用于核酸及其蛋白质复合物的X射线晶体学研究。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. X-ray crystallography is a powerful tool for structure determination of RNA structure, RNA-protein and DNA-protein complexes with high resolution. Derivatization with heavy atoms for phase determination, a long-standing problem in X-ray crystallography, however, has largely slowed down structural determination of nucleic acids with novel folds. One approach to facilitate the structure determination is to label nucleic acids with covalently linked heavy atoms, which enable phase and structure determination. We have developed a novel strategy to derivatize RNA and DNA by replacing oxygen with selenium, and this principle has been demonstrated by X-ray crystallography using MAD phasing method. We are derivatizing DNA and catalytic and binding RNA sequences with novel folds, via chemical and enzymatic synthesis, for X-ray crystallographic studies of nucleic acids and their protein complexes.