Single domain binding molecule
The present invention provides a single domain specific binding molecule having the structure FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 in which the Framework Regions FW1, FW2, FW3a, FW3b, and FW4, the Complementarity Determining Regions CDR1 and CDR3, and the Hypervariable Regions HV2, and HV4 have amino acid sequences as defined which provide a high affinity anti-human serum albumin (HSA) binding domain.
1. A polypeptide comprising
A) a variable domain (VNAR) comprising the Framework Regions FW1, FW2, FW3a, FW3b, and FW4, in which:
i) FW1 comprises TRVDQSPSSLSASVGDRVTITCVLT (SEQ ID NO: 28) or ARVDQSPSSLSASVGDRVTITCVLR (amino acids 1-25 of SEQ ID NO: 67),
ii) FW2 comprises TYWYQQKPGS (SEQ ID NO: 29) or TCWYQQKPGK (amino acids 34-43 of SEQ ID NO: 67),
iii) FW3a comprises GRYSESVN (SEQ ID NO: 30),
iv) FW3b comprises FTLTISSLQPEDFATYYCRA (SEQ ID NO: 31) or FTLTISSLQPEDFATYYCGL (amino acids 65-84 of SEQ ID NO: 67), and
v) FW4 comprises GAGTKVEIK (SEQ ID NO: 32) or CGQGTKVEIK (amino acids 103-112 of SEQ ID NO: 67); or
B) a VNAR having at least 80% identity to the VNAR of A).
2. A polypeptide as claimed in claim 1 , which is humanized.
3. A polypeptide as claimed in claim 1 , in which:
FW1 consists of TRVDQSPSSLSASVGDRVTITCVLT (SEQ ID NO: 28) or ARVDQSPSSLSASVGDRVTITCVLR (amino acids 1-25 of SEQ ID NO: 67).
4. A fusion protein comprising a polypeptide as claimed in claim 1 .
5. A fusion protein as claimed in claim 4 , in which the polypeptide is fused to a biologically active protein.
6. A process for the production of a polypeptide as in claim 1 , comprising the step of expressing a nucleic acid sequence encoding said polypeptide in a host cell.
7. The process as claimed in claim 6 , wherein the polypeptide is humanised.
8. A pharmaceutical composition of a polypeptide as claimed in claim 1 .
9. The pharmaceutical composition as claimed in claim 8 , further comprising at least one of a pharmaceutically acceptable carrier, a pharmaceutically acceptable diluent, a pharmaceutically acceptable adjuvant, and a pharmaceutically acceptable buffer solution.
10. A fusion protein as claimed in claim 5 , in which the biologically active protein is an immunoglobulin domain.
11. A fusion protein as claimed in claim 10 , in which the immunoglobulin domain is an immunoglobulin variable region.
12. A fusion protein as claimed in claim 10 , in which the immunoglobulin domain is an immunoglobulin constant region.
13. A fusion protein as claimed in claim 10 , in which the immunoglobulin domain is an immunoglobulin F c domain.
14. A fusion protein comprising two or more polypeptides as claimed in claim 1 .
15. A fusion protein consisting of two or more polypeptides as claimed in claim 1 .