title: Quantitative analysis of energy transfer between fluorescent proteins in CFP-GBP-YFP and its response to Ca2+.
abstract: This article reports the full characterisation of the optical properties of a biosynthesised protein consisting of fused cyan fluorescent protein, glucose binding protein and yellow fluorescent protein. The cyan and yellow fluorescent proteins act as donors and acceptors for intramolecular fluorescence resonance energy transfer. Absorption, fluorescence, excitation and fluorescence decays of the compound protein were measured and compared with those of free fluorescent proteins. Signatures of energy transfer were identified in the spectral intensities and fluorescence decays. A model describing the fluorescence properties including energy transfer in terms of rate equations is presented and all relevant parameters are extracted from the measurements. The compound protein changes conformation on binding with calcium ions. This is reflected in a change of energy transfer efficiency between the fluorescent proteins. We track the conformational change and the kinetics of the calcium binding reaction from fluorescence intensity and decay measurements and interpret the results in light of the rate equation model. This visualisation of change in protein conformation has the potential to serve as an analytical tool in the study of protein structure changes in real time, in the development of biosensor proteins and in characterizing protein-drug interactions.
authors: Fraunhofer EMFT, Hansastr. 27 D, München, Germany. christof.strohhoefer@emft.fraunhofer.de
authors: Christof
authors: C
authors: Strohhöfer
authors: Thilo
authors: T
authors: Förster
authors: Dušan
authors: D
authors: Chorvát
authors: Peter
authors: P
authors: Kasák
authors: Igor
authors: I
authors: Lacík
authors: Marina
authors: M
authors: Koukaki
authors: Spyridoula
authors: S
authors: Karamanou
authors: Anastassios
authors: A
authors: Economou
mesh_terms: D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D004735:Energy Transfer; D049452:Green Fluorescent Proteins / Q000032:analysis* / Q000096:biosynthesis; D008164:Luminescent Proteins / Q000032:analysis* / Q000096:biosynthesis; D008958:Models, Molecular; D009004:Monosaccharide Transport Proteins / Q000032:analysis* / Q000096:biosynthesis; D014176:Protein Biosynthesis; D011487:Protein Conformation
chemical_list: C485182:Cyan Fluorescent Protein; D008164:Luminescent Proteins; D009004:Monosaccharide Transport Proteins; D049452:Green Fluorescent Proteins; D002118:Calcium