STRUCTURAL STUDIES OF MACROMOLECULES USING SYNCHROTRON RADIATION

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。本提案涉及几个不同系统的研究：a) I型DNA拓扑异构酶；B)鸡脑a-spectrin；c) RNase P的RNA成分结构域I， d)几种DNA结合蛋白。这项工作是基于x射线晶体学。我们多年来一直在研究大肠杆菌DNA拓扑异构酶I和III，并提出了一种催化机制。我们现在正在研究拓扑异构酶I与DNA的相互作用，以及突变蛋白的结构，这可能会揭示反应的细节。1997年，我们利用在SSRL收集的数据解决了鸡脑a-spectrin的两个重复序列的结构。我们现在正在研究包含三个连续重复的新晶体。第三个项目是关于RNase p的RNA成分的结构域I的结构，该结构域长154个碱基，晶体在同步加速器源下衍射到3.3¿¿。最后的项目是关于ZntR的结构，一种金属依赖性的大肠杆菌转录激活剂。晶体很小，我们需要同步辐射来进行MAD相位。

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. This proposal is concerned with the study of several different systems: a) type I DNA topoisomerases; b) chicken brain a-spectrin; c) domain I of the RNA component of RNase P, and d) several DNA binding proteins. The work is based on X-ray crystallography. We have been studying E. coli DNA topoisomerase I and III for a number of years and have proposed a catalytic mechanism. We are now in the process of studying the interactions of topoisomerase I with DNA and also the structure of mutant proteins that could shed light on the details of the reaction. We solved the structure of two repeats of chicken brain a-spectrin in 1997 using data collected at SSRL. We are now studying new crystals that contain three consecutive repeats. The third project is concerned with the structure of domain I of the RNA component of RNase P. This domain is 154 bases long and the crystals diffract to 3.3 ¿¿at a synchrotron source. The final project is concerned with the structure of ZntR, a metal-dependent transcriptional activator of E. coli. The crystals are small and we require synchrotron radiation for MAD phasing.