Transition paths represent the brief moments in a reaction when the energy barrier separating reactants from products is crossed. They contain crucial information about the mechanism of the reaction. In the context of biomolecular folding reactions, where the mechanisms are very complex, they hold the promise of providing previously unavailable information about the transition states that dominate the reaction kinetics. We recently demonstrated the first direct measurements of transition paths in the folding of single biological molecules. Here we will describe how using transition-path measurements on DNA hairpins as a model system to quantify the diffusion coefficient that characterises internal friction, via the transition path times and velocities. The transition path velocities will also be used to estimate the importance of diffusive barrier-recrossing events by determining the transmission factor from classic transition-state theory. Lastly, the shapes of the transition paths will be compared to theoretical estimates, and the variance in the path shapes will be used to show sequence-dependent diversity in the transition paths.

Characterizing the microscopic dynamics of biological macromolecules during folding reactions via direct observation of transition paths

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.