Patent ID: 7381818

Claim:
An oligonucleotide-probe comprising an oligonucleotide portion having a 3′-end and a 5′-end, a minor groove binder moiety attached to at least one of said nucleotide units through a linking group which covalently binds the minor groove binder moiety to the oligonucleotide, and a fluorophore and quencher, said probe having the formula; wherein MB is a minor groove binder; Q is a quencher; Fl is a fluorophore; [A-B]n represents an nucleic acid oligomer having n units, wherein n is an integer of from 5 to 50; each A independently represents a nucleic acid backbone component selected from the group consisting of a sugar phosphate backbone, a modified sugar phosphate backbone, a locked nucleic acid backbone, and a peptidic backbone; and each B independently represents a nucleic acid base, a modified base or a base analog; K is a bond or a linking group; and W is a trivalent linking group that provides sufficient spacing between MB, Fl and [A-B]n such that (i) MB binds in a duplex minor groove formed when said oligonucleotide probe hybridizes to its complementary sequence; (ii) in an unhybridized form, the fluorescence of Fl in said oligonucleotide probe is less than 10% of unquenched fluorescence; and (iii) when said oligonucleotide probe hybridizes to said target sequence, the fluorescence of Fl is at least 50% of its unquenched fluorescence.