Photo-Switching of Protein Dynamical Collectivity

We examine changes in the picosecond structural dynamics with irreversible photobleaching of red fluorescent proteins (RFP) mCherry, mOrange2 and TagRFP-T. Measurements protein dynamical transition using terahertz time-domain spectroscopy show all cases an increase turn-on temperature bleached state. The result is surprising given that there little change surface, thus, solvent held responsible for should not change. A spectral analysis measurements guided by quasiharmonic calculations absorbance reveals indeed independent thermal stability/photostate however shifts to higher temperatures. This first demonstration switching functional observed shift relative indicates required mobile waters necessary motions, is, these motions are more collective. Melting-point reveal photobleached state thermally stable, related RFP’s shows internal water channels as well a uniform atomic root mean squared displacement. These observations consistent previous suggestions form extended light excitation providing O2 access chromophore subsequent fluorescence loss. report same coupling enhancing stability collectivity motions. spectroscopic characterization onsets can be applied generally measure