Method for using heat-resistant mismatch endonuclease

A method of inhibiting amplification of a nucleic acid having a specific nucleotide sequence in a nucleic acid amplification reaction, the method comprising a step of performing the nucleic acid amplification reaction in the presence of the following (a) to (d):

• (a) an oligodeoxynucleotide which is designed to generate one to several mismatches when the oligodeoxynucleotide is hybridized with the nucleic acid having a specific nucleotide sequence or a complementary strand thereof;
• (b) a DNA polymerase;
• (c) at least one pair of oligonucleotide primers;
• and
• (d) a polypeptide having a mismatch endonuclease activity which is at least one polypeptide selected from the group consisting of the following (i) to (vi):
• (i) a polypeptide having an amino acid sequence of SEQ ID NO:1, 7 or 8;
• (ii) a polypeptide having an amino acid sequence which differs from the amino acid sequence of SEQ ID NO:1, 7 or 8 by substitution, deletion, insertion and/or addition of 1 to 10 amino acid residues, and having a mismatch endonuclease activity;
• (iii) a polypeptide having an amino acid sequence which shares at least 75% amino acid sequence identity with the amino acid sequence of SEQ ID NO:1, 7 or 8, and having a mismatch endonuclease activity;
• (iv) a polypeptide having an amino acid sequence of SEQ ID NO:2;
• (v) a polypeptide having an amino acid sequence which differs from the amino acid sequence of SEQ ID NO:2 by substitution, deletion, insertion and/or addition of 1 to 10 amino acid residues other than phenylalanine at position 77, and having a mismatch endonuclease activity;
• and
• (vi) a polypeptide having an amino acid sequence which shares at least 75% amino acid sequence identity with the amino acid sequence of SEQ ID NO:1, in which an amino acid residue corresponding to tryptophan at position 77 in the amino acid sequence of SEQ ID NO:1 is substituted with phenylalanine, and having a mismatch endonuclease activity.