title: Styryl-based wavelength-ratiometric probes: a new class of fluorescent calcium probes with long wavelength emission and a large Stokes' shift.
abstract: We describe the chemical synthesis and fluorescence spectral characterization of a styryl-benzothiazole probe which contains the Ca2+ chelating group BAPTA as an integral part of the chromophoric system. The visible absorption spectrum of this probe displays a dramatic shift in the long wavelength maxima from 508 to 407 nm upon complexation with Ca2+, with a Ca2+ dissociation constant of 1.5 microM. The emission maximum centered at 615 nm is well shifted from the absorption. The emission spectrum displays a small blue shift upon binding Ca2+, allowing this probe to possibly be used as an emission wavelength-ratiometric probe using a single-excitation wavelength. This probe is likely to be the first of a series of long-wavelength ratiometric Ca2+ probes whose structure can be modified for improved quantum yield or altered Ca2+ affinity.
authors.affiliation: University of Maryland, School of Medicine, Department of Biological Chemistry, Baltimore 21201.
authors.forename: E U
authors.initials: EU
authors.lastname: Akkaya
authors.forename: J R
authors.initials: JR
authors.lastname: Lakowicz
mesh_terms: D002118:Calcium / Q000032:analysis*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000138:chemical synthesis; D005456:Fluorescent Dyes / Q000138:chemical synthesis; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence / Q000379:methods; D013343:Styrenes / Q000138:chemical synthesis; D013844:Thiazoles / Q000138:chemical synthesis
chemical_list: D005456:Fluorescent Dyes; D013343:Styrenes; D013844:Thiazoles; C083914:1-(5-(2-(2-N-ethylbenzothiazolinium)ethenyl)-2-aminophenoxy)-2-(2-amino-5-methylphenoxy)ethane-N,N,N',N'-tetraacetic acid; D004533:Egtazic Acid; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium