title: Blue fluorescent protein analogs as chemosensors for Zn²⁺.
abstract: Three chemosensors for Zn²⁺ were designed and synthesized based on the chromophore of the blue fluorescent protein (BFP). Among them, IMMPI (4-((1H-imidazol-2-yl)methylene)-1-methyl-2-phenyl-1H-imidazol-5(4H)-one) contained one BFP chromophore unit, which sequestered Zn²⁺ with nitrogen in the two imidazole rings, while Di-IMMPI-a and Di-IMMPI-o contained two IMMPI units that were connected together using an alkane and a methoxy chain, respectively. All three molecules selectively interacted with Zn²⁺ with a 1:1 mode. Di-IMMPI-a had a dissociation constant <0.03 μM for Zn²⁺, more than 30 folds stronger than that of IMMPI. The fluorescences of IMMPI, Di-IMMPI-a, and Di-IMMPI-o were turned on upon the binding of Zn²⁺, accompanied by the quantum yields enhancing from <0.002 to 0.352, 0.451, and 0.194, respectively. Fluorescence images showed that Di-IMMPI-a responded to Zn²⁺ in cell cytosol. Our work demonstrated the potentiality for the development of practical Zn²⁺ sensors based on the isolated BFP chromophores without the proteinframe.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, People's Republic of China.
authors.forename: Xinxiu
authors.initials: X
authors.lastname: Fang
authors.forename: Haolong
authors.initials: H
authors.lastname: Li
authors.forename: Guiyan
authors.initials: G
authors.lastname: Zhao
authors.forename: Xuexun
authors.initials: X
authors.lastname: Fang
authors.forename: Jingwei
authors.initials: J
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D005453:Fluorescence; D049452:Green Fluorescent Proteins / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D007093:Imidazoles / Q000737:chemistry; D007477:Ions / Q000737:chemistry / Q000302:isolation & purification*; D008164:Luminescent Proteins / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D015032:Zinc / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D007093:Imidazoles; D007477:Ions; D008164:Luminescent Proteins; C409504:blue fluorescent protein, Aequorea victoria; D049452:Green Fluorescent Proteins; D015032:Zinc