Polymerase compositions and methods
Disclosed herein are modified polymerase compositions exhibiting altered polymerase activity, which can be useful in a variety of biological applications. Also disclosed herein are methods of making and using such compositions. In some embodiments, the compositions exhibit altered properties that can enhance their utility in a variety of biological applications. Such altered properties, can include, for example, altered nucleotide binding affinities, altered nucleotide incorporation kinetics, altered photostability and/or altered nanoparticle tolerance, as well as a range of other properties as disclosed herein.
1. A DNA polymerase having a photostability that is at least about 80% under standard photostability assay conditions, wherein the polymerase comprises an amino acid sequence that is at least about 95% identical to the amino acid sequence of SEQ ID NO: 7, further comprising an amino acid substitution selected from the group consisting of: K372G, K372T, K372S, K372R, K372A, K372Q, K372W, K372Y, K372F, wherein the numbering is relative to the amino acid sequence of SEQ ID NO: 7.
2. The DNA polymerase of claim 1 , wherein the polymerase comprises an amino acid sequence that is at least about 98% identical to the amino acid sequence of SEQ ID NO: 7.
3. The DNA polymerase of claim 1 , wherein the polymerase further comprises a mutation reducing 3′ to 5′ exonuclease activity.
4. The DNA polymerase of claim 3 , wherein the mutation reducing 3′ to 5′ exonuclease activity comprises one or more amino acid substitutions at positions selected from the group consisting of: 2, 9, 11, 12, 58, 59, 63, 162, 166, 377 and 385.
5. The DNA polymerase of claim 1 , wherein the polymerase further comprises a mutation increasing the branching ratio of the enzyme with a labeled nucleotide.
6. The DNA polymerase of claim 1 , wherein the polymerase further comprises a mutation increasing the primer extension activity.
7. The DNA polymerase of claim 6 , wherein the mutation increasing the primer extension activity comprises one or more amino acid substitutions selected from the group consisting of: 129 and 339.
8. The DNA polymerase of claim 1 , wherein the polymerase further comprises a mutation increasing the affinity of the polymerase for a particular labeled nucleotide.
9. The DNA polymerase of claim 1 , wherein the DNA polymerase has amino acid leucine at position 383 and amino acid asparagine at position 384.
10. The DNA polymerase of claim 9 , wherein the DNA polymerase exhibits increased polymerase activity relative to the unmodified reference B103 polymerase, SEQ ID NO: 6.
11. The DNA polymerase of claim 9 , further including one or more additional amino acid modifications consisting of one or more amino acid substitutions, additions or deletions at one or more positions selected from the group consisting of: 2, 9, 11, 12, 58, 59, 63, 162, 166, 377 and 385, and the DNA polymerase exhibits reduced exonuclease activity relative to an unmodified B103 polymerase, SEQ ID NO: 6.
12. The DNA polymerase of claim 9 , further including one or more additional amino acid modifications consisting of one or more amino acid substitutions at one or more positions selected from the group consisting of: 365, 370, 371, 372, 481, 507, and 509, and the DNA polymerase exhibits an increased branching ratio and/or increased nucleotide binding affinity relative to a reference modified polymerase of SEQ ID NO: 7.
13. The DNA polymerase of claim 9 , further including one or more additional amino acid modifications consisting of an amino acid substitution at position 380, and the DNA polymerase exhibits increased t pol value (or decreased k pol value) relative to the unmodified B103 polymerase, SEQ ID NO: 6.