Mutated immunoglobulin-binding polypeptides
View Patent ↗A polypeptide with improved alkaline stability, which polypeptide comprises a mutant of a B or C domain of Staphylococcus Protein A, as specified by SEQ ID NO 1 or SEQ ID NO 2, or of Protein Z, as specified by SEQ ID NO 3, wherein at least the glutamine residue at position 15 has been mutated to an amino acid other than asparagine. The invention also discloses multimers of the polypeptide, as well as separation matrices comprising the multimers or polypeptides.
1. A polypeptide with improved alkaline stability, wherein the polypeptide comprises the amino acid sequence of SEQ ID NOS: 6-10, 12, and 13.
2. The polypeptide according to claim 1 , comprising the amino acid sequence selected from the group consisting of SEQ ID NO 6, SEQ ID NO 8, SEQ ID NO 9, SEQ ID NO 10 and SEQ ID NO 13.
3. A multimer comprising a plurality of polypeptide units as defined by claim 1 .
4. The polypeptide according to claim 1 , wherein the polypeptide is the amino acid sequence of SEQ ID NO: 6.
5. The polypeptide according to claim 1 , wherein the polypeptide is the amino acid sequence of SEQ ID NO: 7.
6. The polypeptide according to claim 1 , wherein the polypeptide is the amino acid sequence of SEQ ID NO: 8.
7. The polypeptide according to claim 1 , wherein the polypeptide is the amino acid sequence of SEQ ID NO: 9.
8. The polypeptide according to claim 1 , wherein the polypeptide is the amino acid sequence of SEQ ID NO: 10.
9. The polypeptide according to claim 1 , wherein the polypeptide is the amino acid sequence of SEQ ID NO: 12.
10. The polypeptide according to claim 1 , wherein the polypeptide is the amino acid sequence of SEQ ID NO: 13.
11. A multimer comprising a plurality of polypeptide units as defined by claim 4 .
12. A multimer comprising a plurality of polypeptide units as defined by claim 5 .
13. A multimer comprising a plurality of polypeptide units as defined by claim 6 .
14. A multimer comprising a plurality of polypeptide units as defined by claim 7 .
15. A multimer comprising a plurality of polypeptide units as defined by claim 8 .
16. A multimer comprising a plurality of polypeptide units as defined by claim 9 .
17. A multimer comprising a plurality of polypeptide units as defined by claim 10 .