Nanopore protein conjugates and uses thereof
Described herein are nanopore protein conjugates that can be used in DNA sequencing reactions. The nanopore protein conjugates includes a nanopore protein monomer that is joined to a DNA binding domain. The nanopore protein monomer is available to oligomerize with other nanopore protein monomers, while the DNA binding domain is available to bind to a template DNA strand. In certain examples, the nanopore protein monomer is an alpha-hemolysin monomer or variant thereof and the DNA binding domain is an Sso7d protein or variant thereof, such as an Sso7d-like protein. Also provided are nanopore protein assemblies incorporating the nanopore protein conjugates, along with methods of using the nanopore protein assemblies in sequencing reactions.
1. A nanopore protein conjugate comprising a nanopore protein monomer and a DNA binding domain, wherein the DNA binding domain comprises an Sso7d domain.
2. The nanopore protein conjugate of claim 1 , wherein the nanopore protein monomer comprises an α-hemolysin (α-HL) domain.
3. The nanopore protein conjugate of claim 2 , wherein the α-HL domain comprises an amino acid sequence at least 75% identical to the amino acid sequence set forth as SEQ ID NO: 3 and wherein the Sso7d domain comprises an amino acid sequence having at least 75% sequence identity to the amino acid sequence set forth as SEQ ID NO: 2.
4. The nanopore protein conjugate of claim 3 , wherein the α-HL domain comprises a substitution at a position corresponding to position 1, 2, 3, 4, 9, 12, 17, 35, 47, 106, 128, 129, 130, 131, 144, 149, or 287 of SEQ ID NO: 3 and wherein the substitution comprises one or more positive charges.
5. The nanopore protein conjugate of claim 4 , wherein the α-HL domain further comprises an H144A substitution.
6. The nanopore protein conjugate of claim 4 , wherein the α-HL domain comprises a substitution at a position corresponding to residues T12 and N17.
7. The nanopore protein conjugate of claim 4 , wherein the α-HL domain comprises a substitution selected from one or more of T12K, T12R, N17K, N17R, or combinations thereof.
8. The nanopore protein conjugate of claim 4 , wherein the substitution is selected from the group consisting of T12R, N17K, and N17R.
9. The nanopore protein conjugate of claim 1 , wherein the nanopore protein conjugate comprises an amino acid sequence having at least 80% sequence identity to SEQ ID NO: 5.
10. A heptameric nanopore assembly comprising at least one of the nanopore protein conjugates according to claim 1 .
11. The heptameric nanopore assembly of claim 10 , further comprising a DNA polymerase that is joined to a nanopore monomer of the heptameric nanopore assembly.
12. The heptameric nanopore assembly of claim 11 , wherein the DNA polymerase is joined to the nanopore monomer of the heptameric nanopore assembly via a SpyTag/SpyCatcher linkage.
13. A method for detecting a target molecule, comprising:
providing a chip comprising a nanopore assembly according to claim 10 , wherein the nanopore is disposed within a membrane;
positioning a sensing electrode adjacent or in proximity to the membrane;
contacting the nanopore with a nucleic acid molecule, wherein the nucleic acid molecule is associated with a reporter molecule and comprises an address region and a probe region, wherein the reporter molecule is associated with the nucleic acid molecule at the probe region, and wherein the reporter molecule is coupled to a target molecule;
sequencing the address region while the nucleic acid molecule is in contact with the nanopore to determine a nucleic acid sequence of said address region; and
identifying, with the aid of a computer processor, the target molecule based upon a nucleic acid sequence of the sequenced address region.
14. The nanopore protein conjugate of claim 1 , wherein the nanopore protein conjugate comprises an amino acid sequence having at least 90% sequence identity to SEQ ID NO: 5.
15. The nanopore protein conjugate of claim 1 , wherein the nanopore protein conjugate comprises an amino acid sequence having at least 95% sequence identity to SEQ ID NO: 5.
16. The nanopore protein conjugate of claim 1 , wherein the nanopore protein conjugate comprises an amino acid sequence having at least 98% sequence identity to SEQ ID NO: 5.
17. The nanopore protein conjugate of claim 1 , wherein the nanopore protein conjugate comprises SEQ ID NO: 5.