Fusion proteins forming trimers
The present invention refers to fusion proteins comprising a neck region and carbohydrate recognition domain of a collectin trimerization domain, a linker element and an effector polypeptide. Further the invention refers to a nucleic acid encoding the said fusion protein. The fusion proteins, the nucleic acid, and the cell are suitable as pharmaceutical composition or for therapeutic, diagnostic and/or research applications as described herein.
1. A fusion protein comprising
(i) a collectin family trimerization domain consisting of amino acid residues 221-375 of SEQ ID NO: 21, optionally further consisting of an amino acid substitution at residue 355;
(ii) a linker element; and
(iii) an effector polypeptide selected from the group consisting of a single chain antibody, an antigen binding fragment of a single chain antibody, or an antigen binding fragment of an antibody, wherein the effector polypeptide is located N-terminally of the collectin family neck region
wherein said linker element has 25 or less amino acids.
2. The fusion protein claim 1 , wherein the collectin family trimerization domain consists of the amino acid residues 221-375 of SEQ ID NO: 21.
3. The fusion protein of claim 1 , wherein the amino acid residue 355 in SEQ ID NO: 21 is optionally substituted to a polar amino acid selected from the group consisting of aspartic acid, glutamic acid, asparagine and glutamine.
4. The fusion protein of claim 1 , wherein the effector polypeptide is a single chain antibody against IL4R-alpha.
5. The fusion protein of claim 1 , wherein the linker element has the amino acid sequence of SEQ ID NO: 56, which is GSSGSSGSSGSG.
6. The fusion protein of claim 1 , wherein the linker element has the amino acid sequence of SEQ ID NO: 34, which is GSSGSSGSSGS.
7. The fusion protein of claim 1 , further comprising an N-terminal signal peptide domain.
8. The fusion protein of claim 1 , further comprising a recognition/purification domain selected from the group consisting of a strep-tag domain and a poly-His domain.
9. The fusion protein of claim 1 , wherein the effector polypeptide is a monovalent Fab fragment.
10. The fusion protein of claim 1 , wherein the effector polypeptide is a single chain variable fragment (scFv).
11. The fusion protein of claim 10 , wherein the scFv has a variable domain of a heavy chain located N-terminal to the a variable domain of a light chain.
12. A trimeric complex consisting of three identical fusion proteins of claim 1 .