Photoaffinity Labeling and Active Site Chemistry of 2-5A Synthetase and RNase L

该项目的长期目标是了解两种酶的活性所必需的核苷酸-蛋白质相互作用：依赖dsRNA的2-5A合成酶和依赖2-5A的RNaseL。这些酶在哺乳动物细胞的抗病毒和抗增殖防御机制中发挥着有趣的作用。硫代硫酸盐取代的ATP和2-5A分子为这两种关键酶提供了生化探针，并使酶催化所需的结合和激活过程得以分离。光亲和标记技术被用来检测2-5A合成酶和核糖核酸酶L结合和激活过程中发生的核苷酸-蛋白质相互作用。这个项目研究了两种酶，它们调节细胞中寡核苷酸的水平，并在细胞的防御机制中发挥作用。除了2-5A合成酶/核糖核酸酶L系统在抵御病毒感染中的作用外，该系统还可能参与控制细胞的生长、增殖和分化。根本问题仍然存在，而且正在得到解决。

The long term goal of this project is to understand the nucleotide-protein interactions that are essential for activity of 2 enzymes: the dsRNA-dependent 2-5A synthetase and the 2-5A- dependent RNase L. These enzymes play an intriguing role in the antiviral and antiproliferative defense mechanisms of mammalian cells. Phosphorothioate-substituted ATP and 2-5A molecules have provided beochemical probes of these two key enzymes and have permitted the separation of the binding and activation processes required for enzyme catalysis. Photoaffinity labeling technology is being used to examine the nucleotide-protein interactions occurring during binding and activation of 2-5A synthetase and RNase L. This project investigates 2 enzymes which regulate levels of oligonucleotides in cells and play a role in the cell's defense mechanisms. In addition to the role of the 2-5A synthetase/RNase L system in defense against virus infection, it has been suggested that the system may also be involved in the control of cell growth, proliferation and differentiation. Fundamental questions remain and are being addressed.