Reversible photoswitching fluorescent protein Dronpa can reversibly switch between  fluorescent on-state and non-fluorescent off-state by two radiations. The primary events of photodynamics in Dronpa were elucidated by non-adiabatic ONIOM (CASSCF:AMBER) molecular dynamics simulations. All radiationless decay processes are found mainly to result from one-bond-flip of a bridge C-C bond of the chromophore in the protein, regardless of its protonation state or conformation, rather than hula-twisting. In the off-state protein, trans-cis photoisomerization of the neutral trans chromophore takes place via a rotation around the imidazolinone ring. In the wild-type on-state protein, the anionic cis chromophore mostly remains planar for at least 20 ps. In contrast, in the H193T mutant on-state, faster decay via a rotation of the phenoxy ring or imidazolinone ring of the anionic cis chromophore was found, suggesting that flexibility of the chromophore and its immediate protein  environment is the key to radiationless decays.

Primary events of photodynamics in reversibly photoswitching fluorescent protein Dronpa

241st National Meeting (2011)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.