title: Photophysics and optical switching in green fluorescent protein mutants.
abstract: We demonstrate by using low-temperature high-resolution spectroscopy that red-shifted mutants of green fluorescent protein are photo-interconverted among three conformations and are, therefore, not photostable "one-color" systems as previously believed. From our experiments we have further derived the energy-level schemes governing the interconversion among the three forms. These results have significant implications for the molecular and cell biological applications of the green fluorescent protein family; for example, in fluorescence resonant energy transfer experiments, a change in "color" on irradiation may not necessarily be due to energy transfer but can also arise from a photo-induced conversion between conformers of the excited species.
authors.affiliation: Center for the Study of Excited States of Molecules, Huygens and Gorlaeus Laboratories, University of Leiden, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
authors.forename: T M
authors.initials: TM
authors.lastname: Creemers
authors.forename: A J
authors.initials: AJ
authors.lastname: Lock
authors.forename: V
authors.initials: V
authors.lastname: Subramaniam
authors.forename: T M
authors.initials: TM
authors.lastname: Jovin
authors.forename: S
authors.initials: S
authors.lastname: Völker
mesh_terms: D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000737:chemistry* / Q000235:genetics; D016296:Mutagenesis; D010777:Photochemistry; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins