Utilizing Lifetimes to Suppress Random Coil Features in 2D IR Spectra of Peptides
|Title||Utilizing Lifetimes to Suppress Random Coil Features in 2D IR Spectra of Peptides|
|Publication Type||Journal Article|
|Year of Publication||2011|
|Authors||Middleton CT, Buchanan LE, Dunkelberger EB, Zanni MT|
|Journal||The Journal of Physical Chemistry Letters|
We report that the waiting time delay in 2D IR pulse sequences can be used to suppress signals from structurally disordered regions of amyloid fibrils. At a waiting time delay of 1.0 ps, the random coil vibrational modes of amylin fibrils are no longer detectable, leaving only the sharp excitonic vibrational features of the fibril β-sheets. Isotope labeling with 13C18O reveals that structurally disordered residues decay faster than residues protected from solvent. Since structural disorder is usually accompanied by hydration, we conclude that the shorter lifetimes of random-coil residues is due to solvent exposure. These results indicate that 2D IR pulse sequences can utilize the waiting time to better resolve solvent-protected regions of peptides and that local mode lifetimes should be included in simulations of 2D IR spectra.
|Short Title||J. Phys. Chem. Lett.|