Thermostable polymerase inhibitor compositions and methods
The present disclosure relates to aptamers for temperature-dependent reversible inhibition of thermostable polymerase activity in order to improve sensitivity and specificity of various reactions and assays involving hot start polynucleotide synthesis. Methods for use of the aptamers and related compositions and kits are also provided.
1. A dumbbell aptamer comprising
a single oligonucleotide in a folded configuration, the single oligonucleotide comprising
nucleotides of SEQ ID NO:1, or a variant thereof, covalently linked to
nucleotides of SEQ ID NO:3, or a variant thereof, covalently linked to
nucleotides of SEQ ID NO:2, or a variant thereof, covalently linked to
nucleotides of SEQ ID NO:3, or the variant thereof;
in the folded configuration the single oligonucleotide comprises
a nucleotide stem and two nucleotide loops,
wherein the nucleotide stem comprises
the nucleotides of SEQ ID NO:1, or the variant thereof,
hybridized to
the nucleotides of SEQ ID NO:2, or the variant thereof,
wherein the nucleotides of
SEQ ID NO:1, or the variant thereof, or
SEQ ID NO:2, or the variant thereof,
are split into
a 5′ portion and
a 3′ portion
due to a lack of a covalent bond between adjacent nucleotides of
SEQ ID NO:1 or the variant thereof, or
SEQ ID NO:2, or the variant thereof,
the lack of the covalent bond defining
a 5′ terminus and
a 3′ terminus
of the dumbbell aptamer that are positioned adjacent to one another within the nucleotide stem of the single oligonucleotide in the folded configuration,
wherein:
the variant of SEQ ID NO: 1 has only 1 to 4 nucleotide substitutions in SEQ ID NO:1;
the variant of SEQ ID NO:2 has only 1 to 4 nucleotide substitutions in SEQ ID NO:2;
the variants of SEQ ID NO: 1 and SEQ ID NO:2 are
equal in length to each other, and are
100% complementary to each other along their entire length; and
each of the two nucleotide loops of the single oligonucleotide, in the folded configuration, individually comprise
SEQ ID NO:3, or variants thereof,
the variants of SEQ ID NO:3 having only 1 or 2 nucleotide substitutions in SEQ ID NO: 3.
2. The dumbbell aptamer of claim 1 , wherein
the nucleotides of SEQ ID NO:1, or the variant thereof, are
split into
the 5′ portion and
the 3′ portion,
defining
the 5′ terminus and
the 3′ terminus
within SEQ ID NO:1 or the variant thereof.
3. The dumbbell aptamer of claim 1 , wherein
the nucleotides of SEQ ID NO:2, or the variant thereof, are
split into
the 5′ portion and
the 3′ portion,
defining
the 5′ terminus and
the 3′ terminus
within SEQ ID NO:2 or the variant thereof.
4. The dumbbell aptamer of claim 2 , wherein the nucleotides of SEQ ID NO: 1 lack said covalent bond between nucleotides 8 and 9.
5. The dumbbell aptamer of claim 3 , wherein the nucleotides of SEQ ID NO: 2 lack said covalent bond between nucleotides 8 and 9.
6. The dumbbell aptamer of claim 2 , wherein:
the 5′ terminus, is phosphorylated;
the 3′ terminus is linked to a 3′ capping moiety;
the 5′ terminus, is linked to a 5′ capping moiety; or
the 3′ terminus is linked to the 3′ capping moiety and the 5′ terminus, is linked to the 5′ capping moiety.
7. The dumbbell aptamer of claim 6 , wherein
the 3′ capping moiety is
a propanediol spacer (C3) or
a phosphate.
8. The dumbbell aptamer of claim 6 , wherein
the 5′ capping moiety is an amino group.
9. The dumbbell aptamer of claim 3 , wherein:
the 5′ terminus is phosphorylated;
the 3′ terminus is linked to a 3′ capping moiety;
the 5′ terminus is linked to a 5′ capping moiety; or
the 3′ terminus is linked to the 3′ capping moiety and the 5′ terminus is linked to the 5′ capping moiety.
10. The dumbbell aptamer of claim 9 , wherein
the 3′ capping moiety is
a propanediol spacer (C3) or
a phosphate.
11. The dumbbell aptamer of claim 9 , wherein the 5′ capping moiety is an amino group.
12. A composition comprising
the dumbbell aptamer according to claim 1 and
a thermostable polymerase.
13. The composition of claim 12 , wherein
the molar ratio of
the dumbbell aptamer to
the thermostable polymerase
ranges from
about 2:1 to
about 15:1.
14. The composition of claim 12 , wherein
the molar ratio of
the dumbbell aptamer to
the thermostable polymerase
is about 1:1, 2:1 or 4:1.
15. An aptamer consisting of SEQ ID NO: 110 wherein the 5′ and 3′ ends are ligated.
16. An aptamer comprising SEQ ID NO: 106 or a variant thereof; and
the aptamer further comprising a secondary structure comprising
two nucleotide loops and
a nucleotide stem;
wherein the variant of SEQ ID NO:106 comprises
fewer than 3 nucleotide substitutions in each of the two nucleotide loops,
fewer than 9 nucleotide substitutions in the nucleotide stem, and
fewer than 13 nucleotide substitutions in total.
17. A method for extending a primer, the method comprising
contacting a sample which might contain a target nucleic acid with a reagent composition to generate a reaction mixture;
wherein the reagent composition comprises
the dumbbell aptamer according to claim 1 ,
a thermostable polymerase,
a forward primer specific for the target nucleic acid,
deoxyribonucleotide triphosphates, and
a divalent metal cation.
18. The method of claim 17 , wherein
the ratio of
the dumbbell aptamer to
the thermostable polymerase
ranges from about 2:1 to 15:1.
19. The dumbbell aptamer of claim 1 , wherein
the single oligonucleotide is at least a 56-mer.
20. The dumbbell aptamer of claim 1 , wherein
the single oligonucleotide comprises SEQ ID NO:106.