Abstract's Details

Solution Structure and Thermodynamics of Functional RNA Studied by Small-Angle X-Ray Scattering
Abstract ID	UMTG:6-3
Presenter	Jan Lipfert
Presentation Type	SSRL/LCLS
Full Author List	J. Lipfert (1), D. Herschlag (2), S. Doniach (1,2,4)
Affiliations	(1) Physics Dept., Stanford University (2) Biochemistry Dept., Stanford University (3) Applied Physics Dept., Stanford University (4) Stanford Synchrotron Radiation Laboratory (SSRL)
Category	Bio/Life Sciences
Abstract	Nucleic acids are central to the storage, transmission, and control of genetic information. Recently, a number of mechanisms have been discovered in which RNA molecules regulate genes at the transcriptional and translational levels. In order to carry out their biological function, RNA molecules must fold into intricate 3-D structures, similar to proteins. In contrast to proteins, RNA molecules are highly negatively charged and counterions play a crucial role in RNA folding. We demonstrate that small-angle X-ray scattering can provide low resolution 3-D models for RNA molecules in solution [1]. Using SAXS in combination with chemical footprinting, we have elucidated the thermodynamic landscape of a glycine-binding riboswitch as a function of salt and ligand concentration [2]. Riboswitches are functional RNA molecules that control genes through conformational changes induced upon small-molecule ligand binding. Low resolution models from SAXS provide a first glimpse at the "ON" and "OFF" conformations of this riboswitch [2]. Furthermore, we show that low and intermediate resolution models derived from SAXS in combination with computational modeling can provide a rigorous framework to understand RNA-ion interactions and to distinguish the effects of electrostatic relaxation and specific ion binding on RNA structure [1,3].
Footnotes	[1] Jan Lipfert, Vincent B.Chu, Yu Bai, Daniel Herschlag, and Sebastian Doniach, J. Appl. Cryst. 40:235-239 (2007) [2] Jan Lipfert, Rhiju Das, Vincent B.Chu, Madhuri Kudaravalli, Nathan Boyd, Daniel Herschlag, and Sebastian Doniach, J. Mol. Biol. 365:1393-1406 (2007) [3] Work in preparation
Funding Acknowledgement	This work was supported by the National Institutes of Health Grant PO1 GM0066275. Use of the Advanced Photon Source was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.