Enzyme composition for DNA end repair, adenylation, phosphorylation
Enzyme compositions and their method of use that provide ready-to-use master mixtures. The compositions comprise a modified thermophilic DNA polymerase lacking 5′-3′ and 3′-5′ exonuclease activity premixed with T4 DNA polymerase, Klenow fragment and T4 polynucleotide kinase and all other necessary components, including reaction buffer and nucleoside triphosphates, required to perform DNA blunting, phosphorylation, and single nucleotide extension reactions in one tube and in two steps. Among other benefits, the mixture of different enzymes, buffers and nucleoside triphosphates is stable during prolonged storage.
1. An enzyme composition comprising in a single container a buffer comprising nucleoside triphosphates and a plurality of enzymes separately capable of blunting, phosphorylating and adenylating DNA fragments, with the enzyme capable of adenylating DNA being a chimeric DNA polymerase comprising a thermophilic DNA polymerase fused to a non-specific DNA-binding domain, wherein the thermophilic DNA polymerase lacks 5′-3′ and 3′-5′ exonuclease activity, and with the enzymes capable of blunting and phosphorylating DNA fragments being selected from the group consisting of T4 DNA polymerase, T7 DNA polymerase, Klenow fragment, and T4 polynucleotide kinase, and the composition being stable for at least one week at 4° C.
2. The composition of claim 1 where the chimeric DNA polymerase is a Thermus species thermophilic DNA polymerase fused to non-specific DNA-binding domain.
3. The composition of claim 2 where the chimeric DNA polymerase is a Thermus species polymerase fused to non-specific DNA-binding domain from Sulfolobus family.
4. The composition of claim 1 where the nucleoside triphosphates are dATP, dCTP, dTTP, and dGTP, where the concentration of dATP ranges from 0.4 to 3 mM, the concentration of dCTP ranges from 0.2 to 0.6 mM, the concentration of dTTP ranges from 0.2 to 0.6 mM, and the concentration of dGTP ranges from 0.1 to 0.4 mM.
5. The composition of claim 1 where the concentration of dATP is about 2 mM, the concentration of dCTP is about 0.4 mM, the concentration of dTTP is about 0.4 mM, and the concentration of dGTP is about 0.2 mM.
6. The composition of claim 1 where the buffer further comprises at least one component selected from the group consisting of Tris-HCl, MgCl 2 , DTT, a monovalent metal hydrochloric acid salt selected from NaCl, KCl, and LiCl, ATP, Triton X-100, glycerol, NP 40, EDTA, and Tween 20.
7. The composition of claim 5 where, when present, the concentration of Tris-HCl ranges from 100 mM to 105 mM inclusive at a pH of 8.0 to 8.8; the concentration of MgCl 2 ranges from 15 to 25 mM inclusive, the concentration of DTT ranges from 15 to 30 mM inclusive, the concentration of monovalent metal hydrochloric acid salt ranges from 20 mM to 50 mM inclusive, the concentration of ATP ranges from 1.5 to 2.5 mM inclusive, the concentration of Triton X-100 ranges from 0.1 to 0.4% inclusive, the concentration of glycerol ranges from 10 to 20% inclusive, the concentration of NP 40 ranges from 0.05 to 0.15% inclusive, the concentration of EDTA ranges from 0.02 to 0.1 mM inclusive, and the concentration of Tween 20 ranges from 0.05 to 0.15% inclusive.
8. The composition of claim 1 where the concentration of T4 DNA polymerase ranges from 0.2 to 0.5 U/μl inclusive, the concentration of Klenow fragment ranges from 0.1 to 0.2 U/μl inclusive, and the concentration of T4 polynucleotide kinase ranges from 0.5 U/μl to 1.5 U/μl inclusive.
9. The composition of claim 8 where the concentration of T4 DNA polymerase is about 0.32 U/μl, the concentration of Klenow fragment is about 0.12 U/μl, and the concentration of T4 polynucleotide kinase is about 1 U/μl.
10. The composition of claim 1 where the concentration of the thermophilic DNA polymerase ranges from 0.1 to 0.5 U/μl inclusive.
11. The composition of claim 1 where the concentration of the thermophilic DNA polymerase is about 0.2 U/μl.
12. An enzyme composition comprising in a single container Tris-HCl, MgCl 2 , DTT, KCl, dATP, dCTP, dTTP, dGTP, ATP, Triton X-100, glycerol, NP 40, EDTA, Tween 20, T4 polynucleotide kinase, T4 DNA polymerase, Klenow fragment, and chimeric thermophilic DNA polymerase from Thermus brockianus or Thermus sp. fused to DNA-binding domain from Sulfolobus family, the composition contained in a single container and being storage stable.
13. The composition of claim 12 where the concentration of dATP is at least five times the concentration of each of dCTP, dTTP, and dGTP.