Patent ID: 7888090

Claim:
An isolated mutant O 6 -alkylguanine-DNA alkyltransferase (AGT) of the wild type human AGT encoded by SEQ ID NO: 1, wherein between 6 and 25 amino acids are substituted by other amino acids; and/or 2 to 5 consecutive amino acids at position one, two or three are deleted or added; and/or 1 to 4 amino acids at the N-terminus are deleted; and/or 1 to 40 amino acids at the C-terminus are deleted, and wherein two or more modifications are selected from the group consisting of (A) Cys62 replacement by Ala or Val; (B) Gln115-Gln116 replacement by Ala-Asn, Asn-Asn, Ser-His, Ser-Ser, Pro-Pro, Pro-Ser, Pro-Thr, or Thr-Ser; (D) Gly131-Gly132/Met134-Arg135 replacement by Val-His/Leu-Arg, Lys-Thr/Leu-Ser, Gln-Val/Leu-Ser, or Met-Thr/Met-Val, or Gly131-Gly132/Met134 replacement by Val-His/Leu; (E) Cys150-Ser151-Ser152 replacement by Asn-Ile-Asn, Pro-Leu-Pro, Pro-Arg-Thr, Ser-Phe-Pro-, or Ser-His-Thr-, or Cys150-Ser151 replacement by Phe-Asn or Arg-Asn, or Cys150/Ser152 replacement by His/Thr, Leu/Asn, Leu/Asn, Leu/Pro or Pro/Leu, or Cys150 replacement by Ser or Thr; (F) Pro140/Asn157/Ser159 replacement by Phe/Arg/Glu, or Pro 140/Asn157/Gly160 replacement by Met/Trp/Val, or Asn157/Ser159-Gly160 replacement by Gly/Glu-Ala, Gly/Asn-Trp, Pro/Gln-Cys or Gly-Gln-Trp, or Asn157/Ser159 replacement by Gly/Glu, or Asn157 replacement by Gly or Arg; and (G) truncation after Gly182; and optionally 1 to 10 additional amino acid modifications.