Caustic stable chromatography ligands
The present invention relates to chromatography ligands having improved caustic stability, e.g., ligands based on immunoglobulin-binding proteins such as, Staphylococcal protein A, as well as methods of making and using such ligands.
1. An alkaline-stable chromatography ligand comprising two or more B domains of Staphylococcus protein A (SpA) attached to a chromatography resin at more than one site on the resin, wherein each B domain comprises the amino acid sequence set forth in SEQ ID NO:10 having a mutation to replace the glycine at position 29 with an amino acid other than alanine or tryptophan to reduce Fab binding, as shown in SEQ ID NO:43, wherein the ligand retains at least 95% of its binding capacity after 5 hours incubation in 0.5 M NaOH.
2. The alkaline-stable chromatography ligand of claim 1 , wherein the ligand comprises three or more B domains.
3. The alkaline-stable chromatography ligand of claim 1 , wherein the ligand comprises four or more B domains.
4. The alkaline-stable chromatography ligand of claim 1 , wherein the ligand comprises five or more B domains.
5. The alkaline-stable chromatography ligand of claim 1 , wherein the ligand comprises six or more B domains.
6. The alkaline-stable chromatography ligand of claim 1 , wherein the ligand comprises seven or more B domains.
7. A chromatography matrix comprising a ligand according to claim 1 .
8. The ligand according to claim 1 , wherein the ligand is capable of binding at least 1.5 times, or 2 times, or 3 times, or more of IgG as compared to wtSpA, following exposure to 0.5M NaOH for at least 5 hours.
9. A caustic stable affinity chromatography matrix comprising a ligand comprising three or more, or four or more, or five or more, or six or more, or seven or more B domains of Staphylococcus protein A (SpA) attached to a solid support via multipoint attachment, wherein each B domain comprises the amino acid sequence set forth in SEQ ID NO:10 having a mutation to replace the glycine at position 29 with an amino acid other than alanine or tryptophan to reduce Fab binding, as shown in SEQ ID NO:43, wherein the ligand retains at least 95% of its binding capacity after 5 hours incubation in 0.5 M NaOH.
10. The caustic stable chromatography matrix of claim 9 , wherein the solid support is selected from the group consisting of controlled pore glass, polyvinyl alcohol, zirconium oxide, agarose, polymethacrylate, polyacrylate, polyacrylamide and polystyrene.
11. A caustic stable affinity chromatography ligand comprising three B domains (B3) or four B domains (B4), or five B domains (B5), or six B domains (B6), or seven B domains (B7) of Staphylococcus protein A (SpA) attached to a solid support via multipoint attachment, wherein each B domain comprises the amino acid sequence set forth in SEQ ID NO:10 having a mutation to replace the glycine at position 29 with an amino acid other than alanine or tryptophan to reduce Fab binding, as shown in SEQ ID NO:43, and wherein the extent of caustic stability of ligand is in the order of B3<B4<B5<B6<B7, following exposure of ligand to 0.5M NaOH for at least 5 hours.