title: Carbostyril derivatives as antenna molecules for luminescent lanthanide chelates.
abstract: Luminescent lanthanide complexes consisting of a lanthanide-binding chelate and organic-based antenna molecule have unusual emission properties, including millisecond excited state lifetimes and sharply spiked spectra, compared to standard organic fluorophores. We have previously used carbostyril (cs124, 7-amino-4-methyl-2(1H)-quinolinone) as an antenna molecule (Li and Selvin, J. Am. Chem. Soc., 1995) attached to a polyaminocarboxylate chelate such as DTPA. Here, we report the chelate syntheses of DTPA conjugated with cs124 derivatives substituted on the 1-, 3-, 4-, 5-, 6-, and 8-position. Among them, the DTPA chelate of cs124-6-SO(3)H has similar lifetime and brightness for both Tb(3+) and Eu(3+) compared to the corresponding DTPA-cs124 complexes, yet it is significantly more soluble in water. The Tb(3+) complex of DTPA-cs124-8-CH(3) has significantly longer lifetime compared to DTPA-cs124 (1.74 vs 1.5 ms), indicating higher lanthanide quantum yield resulting from the elimination of back emission energy transfer from Tb(3+) to the antenna molecule. Thiol-reactive forms of chelates were made for coupling to proteins. These lanthanide complexes are anticipated to be useful in a variety of fluorescence-based bioassays.
authors.affiliation: Department of Physics and Center for Biophysics and Computational Biology, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: Pinghua
authors.initials: P
authors.lastname: Ge
authors.forename: Paul R
authors.initials: PR
authors.lastname: Selvin
mesh_terms: D002614:Chelating Agents / Q000032:analysis / Q000737:chemistry*; D006912:Hydroxyquinolines / Q000032:analysis / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000032:analysis / Q000737:chemistry*; D008163:Luminescent Measurements / Q000379:methods*; D015363:Quinolones / Q000032:analysis / Q000737:chemistry*
chemical_list: D002614:Chelating Agents; D006912:Hydroxyquinolines; D028581:Lanthanoid Series Elements; D015363:Quinolones; C010064:carbostyril