Polymerase-nucleotide conjugates for sequencing by trapping
Compositions and methods comprising the use of polymerase-nucleotide conjugates for nucleic acid sequencing and analysis applications are described.
1. A system for identifying a nucleotide, the system comprising:
(a) a nucleic acid binding composition comprising:
(i) a nucleic acid binding moiety comprising a polymerase or a catalytic domain thereof;
(ii) a base-pairing moiety, wherein the base-pairing moieties is connected to the nucleic acid binding moiety via a linker, and wherein the linker has a length effective to allow the base-pairing moiety to pair with a complementary nucleotide in a primed polynucleotide while precluding incorporation of the base-pairing moiety into a 3′ end of the primed polynucleotide, wherein the primed polynucleotide is unlabeled when the primed polynucleotide is disassociated from the base-pairing moiety, wherein:
(A) the polymerase or the catalytic domain thereof comprises a point mutation that renders the polymerase or the catalytic domain thereof incapable of incorporating any nucleotide into the 3′ end of the primed polynucleotide; or
(B) the nucleic acid binding composition lacks sufficient magnesium to render the polymerase or the catalytic domain thereof incapable of incorporating any nucleotide into the 3′ end of the primed polynucleotide; and
(iii) a detectable label coupled to the nucleic acid binding moiety, the base-pairing moiety, or the linker; and
(b) an imaging module comprising an optical waveguide, wherein the imaging module is configured to detect the nucleic acid binding composition bound to the complementary nucleotide in the primed polynucleotide, thereby identifying the complementary nucleotide.
2. The system of claim 1 , wherein the base-pairing moiety comprises a nucleotide or nucleotide analog.
3. The system of claim 1 , wherein the polymerase or the catalytic domain thereof is a reverse transcriptase, or a catalytic domain thereof.
4. The system of claim 1 , wherein the linker comprises a nucleic acid, a peptide, or a polymer.
5. The system of claim 1 , wherein the linker comprises Polyethylene glycol (PEG), and wherein the PEG has an average molecular weight of between about 5 kilodaltons (kDa) and about 20 kDa.
6. The system of claim 2 , wherein the nucleotide or nucleotide analog is conjugated to the linker through the 5′ end of the nucleotide or nucleotide analog.
7. The system of claim 2 , wherein the nucleotide or nucleotide analog comprises a deoxyribonucleotide, a ribonucleotide, a deoxyribonucleoside, or a ribonucleoside.
8. The system of claim 2 , wherein the nucleotide or nucleotide analog has been modified to inhibit elongation during a polymerase reaction or a sequencing reaction.
9. The system of claim 2 , wherein the nucleotide or nucleotide analog lacks a hydroxyl group at a 3′ position of a sugar of the nucleotide or nucleotide analog.
10. The system of claim 2 , wherein the nucleotide or nucleotide analog is modified to contain a blocking group at a 3′ position of a sugar of the nucleotide or nucleotide analog.
11. The system of claim 1 , wherein the nucleic acid binding composition further comprises one or more detectable labels.
12. The system of claim 1 , wherein the nucleic acid binding composition further comprises one or more fluorescent labels.
13. A system for identifying a nucleotide, the system comprising:
(a) a nucleic acid binding composition comprising:
(i) at least one nucleic acid binding moiety comprising a polymerase or a catalytic domain thereof;
(ii) at least four different nucleotides or nucleotide analogs,
wherein each of the at least one nucleic acid binding moieties is tethered to one of the at least four different nucleotides or nucleotide analogs via a linker,
wherein a length of the linker is different for each of the at least four different nucleotides or nucleotide analogs; and
(iii) a detectable label coupled to the nucleic acid binding moiety or the linker,
wherein a nucleotide or a nucleotide analog of the at least four different nucleotides or nucleotide analogs is configured to couple with a complementary nucleotide in a primed polynucleotide, wherein the primed polynucleotide is unlabeled when the primed polynucleotide is disassociated from nucleic acid binding composition, and wherein:
(A) the polymerase or the catalytic domain thereof comprises a point mutation that renders the polymerase or the catalytic domain thereof incapable of incorporating any nucleotide into a 3′ end of the primed polynucleotide; or
(B) the nucleic acid binding composition lacks sufficient magnesium, to render the polymerase or the catalytic domain thereof incapable of incorporating any nucleotide into a 3′ end of the primed polynucleotide; and
(b) an imaging module comprising an optical waveguide, wherein the imaging module is configured to detect the nucleic acid binding composition coupled to the complementary nucleotide in the primed polynucleotide, thereby identifying the complementary nucleotide.
14. The system of claim 13 , wherein one of the at least four different nucleotides or nucleotide analogs comprises a ribonucleotide or a ribonucleoside.
15. The system of claim 13 , wherein the length of the linker is between 1 nanometer (nm) and 1,000 nm.