Notice Board

The Alberta RNA Research and Training Institute presents Dr. Xuesong Shi, candidate for Canada Research Chair (Tier II) in RNA Bioinformatics.

Dr. Xuesong Shi
Beckman Center
Stanford University School of MedicineStanford California

“What do Macromolecules Look Like In Solution”

Tuesday, Dec 8th 2015, 1:40PM-2:55PM

Location: TH241

Everyone is welcome!

Abstract:

Obtaining conformational ensembles, beyond average structures, is extremely challenging but necessary for a deep and complete understanding of the folding and functions of biological RNA, RNA•protein complexes and machines, and engineered RNA nanostructures. Recently we developed a solution-phase scattering technique, small angle X-ray scattering interferometry (XSI), which provides the precise and instantaneous distance distribution in aqueous solution between a pair of Au-nanocrystal probes site-specifically conjugated to a biological macromolecule, thereby revealing the underlying macromolecule ensemble. XSI has been applied to interrogate the fundamental nature of the DNA double helix, to determine the conformational ensemble produced upon introduction of bulge sequences into nucleic acid helices, and to probe the conformational ensemble of a biologically important and recurring RNA motif, the kink-turn, and the effect of L7Ae protein binding on the kink-turn ensemble. Kink-turn RNA is found to exist in an equilibrium between a kinked and unkinked state, and each state is itself an ensemble. Protein association pulls the equilibrium to the kinked state but the kinked ensemble remains a dynamic ensemble rather than being reduced to a single conformation. The dynamic and ensemble nature of RNA•protein motifs are fundamental properties that dictate the assembly and function of RNA•protein complexes and machines.