Poster abstracts
Poster number 146 submitted by Ethan Dixon
Mapping the conformational landscape: AUC as a tool to examine structural diversity
Ethan N Dixon (Chemistry Department, University of Michigan), Alec Garasimowicz (Biophysics Department, University of Michigan), Martin OSteen (Biophysics Department, University of Michigan), Sarah Keane (Biophysics Department, University of Michigan)
Abstract:
The conformational landscape of an RNA species contains vital information for understanding its biological activity and behavior. However, most current structural methods focus on determining a singular tertiary structure, or an individual conformer, of an RNA species and have a limited capacity to characterize structural diversity. In order to explore alternative methods that allow for insight into the variety of tertiary structures that an RNA species adopts, we implemented analytical ultra-centrifugation (AUC) to measure and map out the tertiary structures that unmodified yeast tRNA (Asp) can form at various MgCl2 concentrations. AUC is a non-destructive method that can be conducted at nano-molar range concentrations of an RNA sample under a wide variety of solution conditions and temperatures. This allows researchers to identify the number of conformers in a sample, to quantify the fraction of each conformer, and characterize these structures by their physical properties of sedimentation, diffusion, and anisotropy. By using AUC, we were not only able to validate previous studies in their determination of the equilibrium constant of Mg2+-induced folding of yeast tRNA (Asp), but we were also able to identify the number of tertiary structures observed at each Mg2+ concentration and then further characterize these structures via their diffusion coefficient, their sedimentation coefficient, and their rough geometric shape.
Keywords: Structure, AUC , tRNA