Methods of utilizing thermostable mismatch endonuclease

A composition comprising the following (a) to (c):

• (a) a DNA polymerase;
• (b) at least one pair of oligonucleotide primers;
• and
• (c) at least one polypeptide selected from the group consisting of the following (i) to (iii):
• (i) a polypeptide having an amino acid sequence of SEQ ID NO:1;
• (ii) a polypeptide having an amino acid sequence which differs from the amino acid sequence of SEQ ID NO:1 by substitution, deletion, insertion and/or addition of 1 to several amino acid residues, and having a mismatch endonuclease activity which recognizes and cleaves a G-G, G-T, or T-T mismatch;
• and
• (iii) a polypeptide having an amino acid sequence, which shares at least 95% amino acid sequence identity with the amino acid sequence of SEQ ID NO:1, and having a mismatch endonuclease activity, which recognizes and cleaves a G-G, G-T, or T-T mismatch.

A polypeptide selected from the group consisting of the following (A) to (C):

• (A) a polypeptide having an amino acid sequence of SEQ ID NO:3;
• (B) a polypeptide having an amino acid sequence, which differs from the amino acid sequence of the polypeptide of (A) by substitution, deletion, insertion and/or addition of 1 to several amino acid residues other than amino acid residues at positions 47 and 76, and having a mismatch endonuclease activity, which recognizes and cleaves a A-A, A-C, or C-C mismatch;
• and
• (C) a polypeptide having an amino acid sequence, which shares at least 90% amino acid sequence identity with the amino acid sequence of SEQ ID NO:3, in which amino acid residues corresponding to serine at position 47 and asparagine at position 76 in the amino acid sequence of SEQ ID NO:1 are substituted with other amino acid residues, and having a mismatch endonuclease activity, which recognizes and cleaves a A-A, A-C, or C-C mismatch.

A composition comprising the following (a) to (c):

• (a) a DNA polymerase;
• (b) at least one pair of oligonucleotide primers;
• and
• (c) at least one polypeptide selected from the group consisting of the following (i) to (iii):
• (i) a polypeptide having an amino acid sequence of SEQ ID NO:3;
• (ii) a polypeptide having an amino acid sequence, which differs from the amino acid sequence of the polypeptide of (i) by substitution, deletion, insertion and/or addition of 1 to several amino acid residues other than amino acid residues at positions 47 and 76, and having a mismatch endonuclease activity, which recognizes and cleaves a A-A, A-C, or C-C mismatch;
• and
• (iii) a polypeptide having an amino acid sequence, which shares at least 90% amino acid sequence identity with the amino acid sequence of SEQ ID NO:3, in which amino acid residues corresponding to serine at position 47 and asparagine at position 76 in the amino acid sequence of SEQ ID NO:1 are substituted with other amino acid residues, and having a mismatch endonuclease activity, which recognizes and cleaves a A-A, A-C, or C-C mismatch.