Download Ultrafast Solvation: Investigating Molecular Forces in Protein Folding November 12, 2010

November 12, 2010
Ultrafast Solvation: Investigating Molecular
Forces in Protein Folding
Christina M. Othon
Assistant Professor of Physics
Wesleyan University
Protein folding is largely driven by non-classical forces such as the hydrophobic effect, van
der Waals interactions, and hydrogen bonding. Unlike discrete ionic or covalent bonding,
the cooperative behavior of these interactions drives the spontaneous folding and unfolding of large macromolecules. The ability to manipulate these large-scale conformational
changes will require a complete understanding of solvent-protein interactions. We
investigate solvent-protein interactions by measuring the photoexcitation of the natural
amino acid tryptophan using ultrafast fluorescence spectroscopy. This allows us to probe
the solvent dynamics at the surface of the molecule. Using this technique we investigated
how the variation of solvent properties affects protein conformation. We followed the
dynamic hydration changes that took place around an un-folding protein, and found a
cooperative unfolding transition involving an intermediate state which is stabilized via long
range van der Waals forces. These results provide quantitative results which can help
advance protein folding theory and will open new avenues for protein engineering and
biotechnology applications.