title: Structural basis for reversible photobleaching of a green fluorescent protein homologue.
abstract: Fluorescent protein (FP) variants that can be reversibly converted between fluorescent and nonfluorescent states have proven to be a catalyst for innovation in the field of fluorescence microscopy. However, the structural basis of the process remains poorly understood. High-resolution structures of a FP derived from Clavularia in both the fluorescent and the light-induced nonfluorescent states reveal that the rapid and complete loss of fluorescence observed upon illumination with 450-nm light results from cis-trans isomerization of the chromophore. The photoinduced change in configuration from the well ordered cis isomer to the highly nonplanar and disordered trans isomer is accompanied by a dramatic rearrangement of internal side chains. Taken together, the structures provide an explanation for the loss of fluorescence upon illumination, the slow light-independent recovery, and the rapid light-induced recovery of fluorescence. The fundamental mechanism appears to be common to all of the photoactivatable and reversibly photoswitchable FPs reported to date.
authors.affiliation: Departments of Chemistry and Physics, and Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA.
authors.forename: J Nathan
authors.initials: JN
authors.lastname: Henderson
authors.forename: Hui-Wang
authors.initials: HW
authors.lastname: Ai
authors.forename: Robert E
authors.initials: RE
authors.lastname: Campbell
authors.forename: S James
authors.initials: SJ
authors.lastname: Remington
mesh_terms: D000818:Animals; D037421:Anthozoa; D018360:Crystallography, X-Ray; D019020:Directed Molecular Evolution; D049452:Green Fluorescent Proteins / Q000737:chemistry* / Q000378:metabolism*; D038761:Photobleaching; D015202:Protein Engineering; D040681:Structural Homology, Protein
chemical_list: C485182:Cyan Fluorescent Protein; D049452:Green Fluorescent Proteins