Homogeneous detection of a target through nucleic acid ligand-ligand beacon interaction
First Claim
1. A method for detecting a target molecule in a test mixture suspected of containing said target molecule, the method comprising:
- A) i) providing a nucleic acid ligand capable of binding to said target molecule, said nucleic acid ligand comprising a first sequence A and a second sequence B wherein A and B are partially complementary sequences that form an imperfect intramolecular duplex, wherein said duplex unwinds upon the binding of said target to said nucleic acid ligand, and wherein said sequences A and B are able to participate in extramolecular hybridization reactions only when said duplex is unwound;
ii) providing a first cascade nucleic acid comprising a first sequence A′ and
a second sequence C′
, wherein A′ and
C′
are partially complementary sequences that form an imperfect intramolecular duplex, wherein A′
is exactly complementary to sequence A and wherein the duplex of said first cascade nucleic acid unwinds upon the hybridization of A′
to an unpaired A sequence;
iii) providing a second cascade nucleic acid, said second cascade nucleic acid comprising a first sequence B′ and
a second sequence C wherein B′ and
C are partially complementary sequences that form an imperfect intramolecular duplex, wherein B′
is exactly complementary to sequence B and C is exactly complementary to C′
, and wherein the duplex of said second cascade nucleic acid unwinds upon the hybridization of B′
to an unpaired B sequence or upon the hybridization of C′
to an unpaired C sequence;
iv) providing a third cascade nucleic acid, said third cascade nucleic acid comprising a first sequence A and a second sequence B that form an imperfect intramolecular duplex and wherein the duplex of said third cascade nucleic acid unwinds upon the hybridization of A to A′
or upon the hybridization of B to B′
;
B) contacting said test mixture suspected of containing said target molecule with said nucleic acid ligand, whereby said duplex of said nucleic acid ligand unwinds in the presence of said target whereby sequences A and B become available for extramolecular hybridization;
C) contacting said test mixture and said nucleic acid ligand with said first, second, and third cascade nucleic acids, wherein the presence of unpaired A and B sequences on said nucleic acid ligand triggers a cascade of intermolecular hybridization involving said cascade nucleic acids in which intermolecular hybridization takes place between A and A′
, between B and B′ and
between C and C′
, leading to the formation of a multimolecular hybridization complex;
D) detecting the presence of said multimolecular hybridization complex.
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Accused Products
Abstract
A method for detecting a target molecule in a test mixture suspected of containing said target molecule is described. The nucleic acid ligand capable of binding to the target molecule has a first sequence A and a second sequence B, which are partially complementary sequences that form an imperfect intramolecular duplex, which unwinds upon the binding of the target to the nucleic acid ligand. Sequences A and B are able to participate in extramolecular hybridization reactions only when the duplex is unwound. Three different cascade nucleic acids contain a first sequence and a second sequence, which are partially complementary sequences. At least one sequence is exactly complementary to A or B. The second sequence may be complementary to A or B, or may be a third sequence C, or its complement. The test mixture suspected of containing the target molecule is contacted with the nucleic acid ligand, causing the duplex of the nucleic acid ligand to unwind such that sequences A and B become available for extramolecular hybridization. This mixture is contacted with the first, second, and third cascade nucleic acids so that the unpaired A and B sequences triggers a cascade of intermolecular hybridization involving the cascade nucleic acids in which intermolecular hybridization takes place between A and its complement, B and its complement, and between C its complement, leading to the formation of a multimolecular hybridization complex. The presence of the multimolecular hybridization complex is then detected.
108 Citations
3 Claims
-
1. A method for detecting a target molecule in a test mixture suspected of containing said target molecule, the method comprising:
-
A) i) providing a nucleic acid ligand capable of binding to said target molecule, said nucleic acid ligand comprising a first sequence A and a second sequence B wherein A and B are partially complementary sequences that form an imperfect intramolecular duplex, wherein said duplex unwinds upon the binding of said target to said nucleic acid ligand, and wherein said sequences A and B are able to participate in extramolecular hybridization reactions only when said duplex is unwound;
ii) providing a first cascade nucleic acid comprising a first sequence A′ and
a second sequence C′
, wherein A′ and
C′
are partially complementary sequences that form an imperfect intramolecular duplex, wherein A′
is exactly complementary to sequence A and wherein the duplex of said first cascade nucleic acid unwinds upon the hybridization of A′
to an unpaired A sequence;
iii) providing a second cascade nucleic acid, said second cascade nucleic acid comprising a first sequence B′ and
a second sequence C wherein B′ and
C are partially complementary sequences that form an imperfect intramolecular duplex, wherein B′
is exactly complementary to sequence B and C is exactly complementary to C′
, and wherein the duplex of said second cascade nucleic acid unwinds upon the hybridization of B′
to an unpaired B sequence or upon the hybridization of C′
to an unpaired C sequence;
iv) providing a third cascade nucleic acid, said third cascade nucleic acid comprising a first sequence A and a second sequence B that form an imperfect intramolecular duplex and wherein the duplex of said third cascade nucleic acid unwinds upon the hybridization of A to A′
or upon the hybridization of B to B′
;
B) contacting said test mixture suspected of containing said target molecule with said nucleic acid ligand, whereby said duplex of said nucleic acid ligand unwinds in the presence of said target whereby sequences A and B become available for extramolecular hybridization;
C) contacting said test mixture and said nucleic acid ligand with said first, second, and third cascade nucleic acids, wherein the presence of unpaired A and B sequences on said nucleic acid ligand triggers a cascade of intermolecular hybridization involving said cascade nucleic acids in which intermolecular hybridization takes place between A and A′
, between B and B′ and
between C and C′
, leading to the formation of a multimolecular hybridization complex;
D) detecting the presence of said multimolecular hybridization complex. - View Dependent Claims (2, 3)
-
Specification