Protein dynamics, the population of and interconversion among multiple states, are often evoked to explain function. The experimental characterization of protein dynamics to fully uncover their role however is challenged by both the spatial heterogeneity of proteins and the rapid interconversion of potentially important conformational states. Our group combines the inherent temporal resolution of linear and two-dimensional infrared spectroscopy with the spatial resolution afforded by site-selective incorporation of vibrational reporter groups that provide frequency-resolved absorptions to characterize rapidly occurring changes in local environments in proteins. I will share several vignettes about our application of this approach toward understanding the molecular recognition of protein systems: Src homology 3 domain recognition of proline-rich motifs, cytochrome P450cam regioselectivity, and plastocyanin recognition by cytochrome f. Our studies resolve rapid dynamics at specific locations in the proteins and implicate their involvement in function.
Megan Thielges (University of Indiana)