MECHANISM AND KINETICS OF RNA FOLDING BY SAXS

这个子项目是众多研究子项目之一

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. RNAs perform many biological functions by folding into specific three-dimensional structures. Understanding how RNAs fold is crucial for understanding the assembly of RNA-protein complexes such as the ribosome, the regulation of gene expression by RNA, and the engineering of RNA sensors and "riboswitches". In the presence of counterions, RNAs collapse into compact intermediates, which subsequently fold into the native tertiary structure. Theory suggests that competition between different collapse mechanisms partitions the RNA population along alternate folding pathways, some of which lead to kinetically trapped and misfolded intermediates. Some of the important questions in RNA folding include (1) the kinetic mechanism of nucleation and collapse, (2) how cations and RNA sequence determine the specificity of the initial collapse transition, and (3) the distribution of structures in the ensemble of unfolded RNA. We plan to address these questions using time resolved small angle X-ray scattering (SAXS) on a group I ribozyme from the bacterium Azoarcus. The proposed studies will provide insight into the nucleation of RNA tertiary structure and provide experimental tests of theoretical models of electrostatic interactions in unfolded and folded RNAs. The work will include both wild type and mutants of Azoarcus and comparison to the more widely studied Tetrahymena intron.