Dark quenchers for donor-acceptor energy transfer
The present invention provides a family of dark quenchers, termed Black Hole Quenchers (“BHQs”), that are efficient quenchers of excited state energy but which are themselves substantially non-fluorescent. Also provided are methods of using the BHQs, probes incorporating the BHQs and methods of using the probes.
1. A quencher-labeled conjugate, comprising a quencher moiety and a conjugated substance, wherein the quencher moiety comprises structure (Q):
wherein:
at least one aryl carbon is substituted with an electron-withdrawing group; and
at least one aryl carbon is substituted with an electron-donating group,
and further wherein the quencher moiety is covalently linked to the conjugated substance at an aryl carbon, optionally by way of a linker; and
the conjugated substance is selected from an amino acid, a polypeptide, a nucleoside, a nucleotide, a polynucleotide and protected forms thereof.
2. The quencher-labeled conjugate of claim 1 in which the conjugated substance is a polynucleotide.
3. The quencher-labeled conjugate of claim 2 which further comprises a fluorescent moiety covalently attached to the polynucleotide, the fluorescence of which is capable of being quenched by the quencher moiety when the fluorescent and quencher moieties are in close proximity to one another.
4. The quencher-labeled conjugate of claim 3 in which the 3′-terminus of the polynucleotide cannot be extended by a polymerase.
5. The quencher-labeled conjugate of claim 4 in which the quencher moiety is attached to the 3′-terminal nucleotide of the polynucleotide and the fluorescent moiety is attached to the 5′-terminal nucleotide of the polynucleotide.
6. The quencher-labeled conjugate of claim 4 in which the quencher moiety is attached to the 3′-terminus of the polynucleotide.
7. The quencher-labeled conjugate of claim 4 in which the fluorescent moiety is attached to the 5′-terminus of the polynucleotide.
8. The quencher-labeled conjugate of claim 4 in which the fluorescent moiety is attached to the 3′-terminal nucleotide of the polynucleotide and the quencher moiety is attached to the 5′-terminal nucleotide of the polynucleotide.
9. The quencher-labeled conjugate of claim 4 in which the fluorescent moiety is attached to the 3′-terminus of the polynucleotide.
10. The quencher-labeled conjugate of claim 4 in which the quencher moiety is attached to the 5′-terminus of the polynucleotide.
11. A quencher-labeled conjugate, comprising a quencher moiety and a conjugated substance, wherein the quencher moiety comprises structure (Q):
wherein:
at least one aryl carbon is substituted with an electron-withdrawing group; and
at least one aryl carbon is substituted with an electron-donating group,
and further wherein the quencher moiety is covalently linked to the conjugated substance at an aryl carbon, optionally by way of a linker
in which the conjugated substance is a polypeptide.
12. The quencher-labeled conjugate of claim 1 in which the quencher moiety (Q) comprises structure (Q1):
wherein:
R 1 , R 2 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 and R 14 are each, independently of one another, selected from hydrogen, an electron-withdrawing group and an electron-donating group, or, alternatively R 4 may be taken together with R 5 or R 6 may be taken together with R 7 to form a benzo group,
with the provisos that: (i) at least one of R 1 , R 2 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 or R 14 is an electron-withdrawing group; and (ii) at least one of R 1 , R 2 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 or R 14 is an electron-donating group.
13. The quencher-labeled conjugate of claim 12 in which the electron-withdrawing groups are each, independently of one another, selected from NO 2 , CN, CF 3 , CO 2 H, CO 2 R′, C(O)NH 2 , N(O)NHR′, C(O)NR′R′, CHO, C(O)R′, SO 2 R′, SO 2 CF 3 , SO 2 OR′, SO 3 H, NO and C 5 -C 14 aryl, where R′ is H, C 1 -C 12 alkyl or C 5 -C 14 aryl.
14. The quencher-labeled conjugate of claim 12 in which R 10 is NO 2 .
15. The quencher-labeled conjugate of claim 12 in which at least one of R 1 , R 2 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 and R 14 is OCH 3 .
16. The quencher-labeled conjugate of claim 12 in which Q1 is selected from: