Ligase mutant
Ligase mutants of the following (1), (2), or (3): (1) a ligase mutant comprising an amino acid sequence showing 95% or more identity to the amino acid sequence of SEQ ID NO: 1, and having a nucleic acid-linking activity; (2) a ligase mutant comprising an amino acid sequence showing 90% or more identity to the amino acid sequence of SEQ ID NO: 2, and having a nucleic acid-linking activity; or (3) a ligase mutant comprising an amino acid sequence showing 97% or more identity to the amino acid sequence of SEQ ID NO: 3, and having a nucleic acid-linking activity, have excellent properties.
1. A ligase mutant selected from the group consisting of:
(1) a ligase mutant comprising an amino acid sequence showing 95% or more identity to the amino acid sequence of SEQ ID NO: 1, and having a nucleic acid-linking activity;
(2) a ligase mutant comprising an amino acid sequence showing 90% or more identity to the amino acid sequence of SEQ ID NO: 2, and having a nucleic acid-linking activity; and
(3) a ligase mutant comprising an amino acid sequence showing 97% or more identity to the amino acid sequence of SEQ ID NO: 3, and having a nucleic acid-linking activity.
2. The ligase mutant according to claim 1 , having a nucleic acid-linking activity for a nucleic acid which is a single-stranded RNA or double-stranded RNA optionally containing DNA and/or a modified nucleic acid.
3. A method for producing a nucleic acid product, said method comprising linking two or more nucleic acid materials in the presence of a ligase mutant according to claim 1 to form said nucleic acid product,
wherein said two or more nucleic acid materials are selected from the group consisting of one or more single-stranded nucleic acid materials, one or more double-stranded nucleic acid materials, and a mixture thereof.
4. The method according to claim 3 , wherein said two or more nucleic acid materials are RNA.
5. The method according to claim 3 , wherein said two or more nucleic acid materials are four or more single-stranded RNAs.
6. The method according to claim 3 , wherein said nucleic acid product contains a complementary portion having a base length of 12 to 27.
7. The method according to claim 3 , wherein said two or more nucleic acid materials are DNA and/or a modified nucleic acid.
8. The method according to claim 3 , wherein said two or more nucleic acid materials have a concentration of 1 μM or more.
9. The method according to claim 3 , wherein said nucleic acid product is siRNA.
10. A polynucleotide encoding a ligase mutant according to claim 1 .
11. A polynucleotide encoding a ligase mutant according to claim 2 .
12. An expression vector comprising a polynucleotide according to claim 10 .
13. An expression vector comprising a polynucleotide according to claim 11 .
14. A transformed microorganism comprising an expression unit comprising a polynucleotide encoding a ligase mutant according to claim 1 , and a promoter operably linked to the polynucleotide.
15. A transformed microorganism comprising an expression unit comprising a polynucleotide encoding a ligase mutant according to claim 2 , and a promoter operably linked to the polynucleotide.
16. A method for producing a ligase mutant, said method comprising producing a ligase mutant according to claim 1 using a transformed microorganism comprising an expression unit comprising a polynucleotide encoding said ligase mutant and a promoter operably linked to said polynucleotide.