Ultrafast Dynamics of Protein Proton Transfer on Short Hydrogen Bond Potential Energy Surfaces: S65T/H148D GFP.

Abstract

Ultrafast proton transfer dynamics on a short H-bond in a protein were studied through the time-resolved fluorescence of the S65T/H148D green fluorescent protein (GFP) mutant. In response to the change in chromophore pK(a) upon excitation, the donor-proton-acceptor structure evolves on a sub-100 fs time scale, followed by picosecond time scale vibrational cooling and host structure reorganization.