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OCCI Lecture Series: Professor Rebecca Jockusch
October 28, 2016 at 10:00 AM to 11:30 AM
| Location: | 208 Tory Building |
| Cost: | Free |
New Tools to Probe Biomolecules in Minimalist Environments
Professor Rebecca Jockusch
Department of Chemistry
University of Toronto
Abstract: The function of biological molecules is dependent on properties including biomolecular structure, stability, dynamics and interactions. While the complexity of the native environment is desirable for function, isolation of biological molecules from their normal environment provides valuable simplification, allowing study of their intrinsic properties. My research program combines trapping mass spectrometry with optical spectroscopic techniques in order to characterize properties of biomolecules and their complexes in a highly-controlled gas-phase environment. In particular, we are pursuing the use of fluorescence and fluorescence resonance energy transfer (FRET) techniques to probe the conformation of relatively large gaseous ions and complexes. Here, I present results from FRET experiments on the B1 domain of protein G (GB1) after it was transferred into the gas phase using electrospray ionization (ESI). Energy transfer measurements of isolated GB1 show a marked decrease in the FRET efficiency with increasing number of charges on the gaseous protein, which suggests a Coulombically driven unfolding and expansion of its structure. This lies in stark contrast to the pH stability of GB1 in solution and highlights the importance of solvent effects in maintaining the protein fold. I will also discuss some of our recent work benchmarking the intrinsic (gas-phase) photophysical properties of ionic dyes that are commonly used in chemistry and the
biosciences and examining how these properties are modulated by specific molecular interactions. Together, this work forms a basis from which to better understand how noncovalent
interactions, including those with the solvent, affect the properties of molecules ranging in size from small organic dyes to proteins.