Foki nuclease domain mutant

A nuclease domain mutant of a FokI protein or a homologous protein thereof, which has a mutation listed in any of (a) to (d) below, and whose nuclease activity is improved by the mutation:

• (a) at least one mutation selected from the group consisting of a substitution of amino acid with Met at position 386 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Arg at position 399 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Tyr at position 421 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Phe at position 424 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Leu at position 432 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Val at position 433 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Asn at position 448 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Be at position 466 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Ala at position 484 in the FokI protein or the corresponding site in the homologous protein, and a substitution of amino acid with Leu at position 486 in the FokI protein or the corresponding site in the homologous protein;
• (b) at least one mutation selected from the group consisting of a substitution of amino acid with Pro at position 418 of a wild-type protein or the corresponding site of a homologous protein thereof, a substitution of amino acid with Leu at position 420 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Val at position 452 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Arg at position 473 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with His at position 486 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Val at position 490 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Leu at position 498 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Lys at position 542 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Arg at position 559 in the FokI protein or the corresponding site in the homologous protein, and a substitution of amino acid with Ser at position 570 in the FokI protein or the corresponding site in the homologous protein;
• (c) at least one mutation selected from the group consisting of a substitution of amino acid with Met at position 386 of a wild-type protein or the corresponding site of a homologous protein thereof, a substitution of amino acid with Phe at position 395 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Arg at position 399 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Tyr at position 421 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Phe at position 424 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Leu at position 432 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Val at position 433 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Asn at position 448 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Ala at position 484 in the FokI protein or the corresponding site in the homologous protein, and a substitution of amino acid with Leu at position 486 in the FokI protein or the corresponding site in the homologous protein;
• and
• (d) at least one mutation selected from the group consisting of a substitution of amino acid with Pro at position 385 of a wild-type protein or the corresponding site of a homologous protein thereof, a substitution of amino acid with Ala at position 395 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Met at position 427 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Val at position 452 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Phe at position 460 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Arg at position 473 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with His at position 481 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Gln at position 490 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Thr at position 542 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Arg at position 559 in the FokI protein or the corresponding site in the homologous protein, a substitution of amino acid with Ser at position 570 in the FokI protein or the corresponding site in the homologous protein.