Ultrafast energy relaxation dynamics of amide I vibrations coupled with protein-bound water molecules.

ABSTRACT: The influence of hydration water on the vibrational energy relaxation in a protein holds the key to understand ultrafast protein dynamics, but its detection is a major challenge. Here, we report measurements on the ultrafast vibrational dynamics of amide I vibrations of proteins at the lipid membrane/H2O interface using femtosecond time-resolved sum frequency generation vibrational spectroscopy. We find that the relaxation time of the amide I mode shows a very strong dependence on the H2O exposure, but not on the D2O exposure. This observation indicates that the exposure of amide I bond to H2O opens up a resonant relaxation channel and facilitates direct resonant vibrational energy transfer from the amide I mode to the H2O bending mode. The protein backbone motions can thus be energeticall

SUBMITTER: Tan J 

PROVIDER: S-EPMC6397197 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature