Structural basis for reversible photoswitching in Dronpa

• DOI: 10.1073/pnas.0700629104
• Publication Date: 2007-07-24T01:18:21Z
• Authors: Martin Andresen; Andre C. Stiel; Simon Trowitzsch; Gert Weber; Christian Eggeling; Markus C. Wahl; Stefan W. Hell; Stefan Jakobs
• Keywords: Chromophore; Molecular switch; Dark state; Fluorescent protein

Dronpa is a novel GFP-like fluorescent protein with exceptional light-controlled switching properties. It may be reversibly switched between on-state and nonfluorescent off-state by irradiation light. To elucidate the molecular basis of mechanism, we generated switchable crystals. Using these crystals determined elusive dark-state structure at 1.95-A resolution. We found that photoswitching results in cis-trans isomerization chromophore accompanied complex structural rearrangements four nearby amino acid residues. Because this cascade intramolecular events, exposed to distinct electrostatic surface potentials, which are likely influence protonation equilibria chromophore. suggest comprehensive model for light-induced connecting different states