10月16日: Nucleic Acid Structure and Dynamics: Perspectives from Spin Labeling
报告人：Peter Z. Qin
(Department of Chemistry, University of Southern California, Los Angeles, California,)
In site-directed spin labeling (SDSL), a stable nitroxide radical is covalently attached at a specific location within a macro-molecule, and structural and dynamic information at the labeling site is obtained via electron paramagnetic resonance (EPR) spectroscopy. My group pioneered the development of a family of nitroxide probes, called the R5-series, which can be attached in an efficient and cost-effective manner to a specific phosphorothioate backbone position at arbitrary DNA or RNA sequences. Using these nucleotide-independent nitroxide probes in conjunction with pulse and continuous-wave EPR spectroscopy, we have obtained structural and dynamic information in systems that are difficult to study by other methods. In this presentation, I will describe recent work on mapping global structure of a non-coding RNA complex;[2, 3] probing nanosecond motions in a large RNA enzyme; as well as investigating sequence-dependent DNA shape[5-7] and its role in specific recognition between the p53 tumor repressor and its DNA targets.