title: Singlet oxygen photosensitization by EGFP and its chromophore HBDI.
abstract: The photosensitization of reactive oxygen species and, in particular, singlet oxygen by proteins from the green fluorescent protein (GFP) family influences important processes such as photobleaching and genetically targeted chromophore-assisted light inactivation. In this article, we report an investigation of singlet oxygen photoproduction by GFPs using time-resolved detection of the NIR phosphorescence of singlet oxygen at 1275 nm. We have detected singlet oxygen generated by enhanced (E)GFP, and measured a lifetime of 4 micros in deuterated solution. By comparison with the model compound of the EGFP fluorophore 4-hydroxybenzylidene-1,2-dimethylimidazoline (HBDI), our results confirm that the beta-can of EGFP provides shielding of the fluorophore and reduces the production of this reactive oxygen species. In addition, our results yield new information about the triplet state of these proteins. The quantum yield for singlet oxygen photosensitization by the model chromophore HBDI is 0.004.
authors.affiliation: Grup d'Enginyeria Molecular, Institut Químic de Sarrià, Barcelona, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Jiménez-Banzo
authors.forename: Santi
authors.initials: S
authors.lastname: Nonell
authors.forename: Johan
authors.initials: J
authors.lastname: Hofkens
authors.forename: Cristina
authors.initials: C
authors.lastname: Flors
mesh_terms: D049452:Green Fluorescent Proteins / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000528:radiation effects; D026082:Singlet Oxygen / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D017319:Photosensitizing Agents; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D026082:Singlet Oxygen