Fluorescent energy tranfer label comprising a cyanine dye as donor and an acceptor bonded to a backbone

摘要

A fluorescent label comprises two fluorophores bonded to a backbone in an energy transfer relationship, one of which is a donor fluorophore which is cyanine dye (especially 3-( epsilon -carboxypentyl)-3'-ethyl-5,5'-dimethyloxacarbocyanine and 3-( epsilon -carboxypentyl)-3'-ethyloxacarbocyanine) having a quantum yield of from 0.01 to 0.25, and the other is an acceptor fluorophore, preferably a xanthene dye (particularly a fluorescein or rhodamine) having a quantum yield of at least 0.3. The cyanine dye may have an absorbtion maximum in a wavelength range of from 400 to 900 nm, and the acceptor fluorophore one of 450 to 1000 nm. The backbone may be an oligonucleotide, preferably of from 5 to 30 nucleotides. The donor may be bonded to the 5'-terminus, whilst that and the acceptor may be separated by from 1 to 15 nucleotides. The labels may be used in the sequencing of nucleic acids, or in the identification and detection of nucleic acid fragments (single-stranded or double-stranded) in a mixture thereof.