CRYSTAL STRUCTURE OF THE CATALYTIC CORE OF AN RNA POLYMERASE RIBOZYME

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 I类连接酶核酶促进小的寡核苷酸底物和它自己的5‘末端之间3’-5‘磷酸二酯键的形成，要求亲核体和亲核体都位于Watson-Crick对的上下文中。这种化学作用是迄今观察到的最快的催化RNA之一，相当于模板指导的RNA聚合的一次周转，这是RNA世界所必需的活动。事实上，连接酶的微小变体能够催化使用外源核苷三磷酸盐的高保真模板指导的RNA聚合，而连接酶构成了一般RNA聚合酶核酶的催化核心。为了了解RNA催化的RNA依赖的RNA聚合的基础，我们已经着手解决连接酶的晶体结构。

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. The class I ligase ribozyme promotes the formation of a 3'-5' phosphodiester linkage between a small oligonucleotide substrate and its own 5' terminus, requiring both the nucleophile and electrophile to be situated within the context of a Watson-Crick pair. This chemistry  among the fastest yet observed for any catalytic RNA  is equivalent to a single turnover of template-directed RNA polymerization, an activity that would have been requisite in the RNA World. Indeed, minor variants of the ligase are capable of catalyzing high-fidelity template-directed RNA polymerization using exogenous nucleoside triphosphates, and the ligase constitutes the catalytic core for a general RNA polymerase ribozyme. To understand the basis of RNA-catalyzed RNA-dependent RNA polymerization, we have set out to solve the crystal structure of the ligase.