| abstract |
Polypeptide, comprising a complement factor B protein analog, wherein (A) the complement factor B analog comprises a substitution of a free cysteine amino acid; (B) Free cysteine corresponds to amino acid 292 of SEQ ID NO: 1, as determined by aligning the amino acid sequence of the complement factor B analog with the amino acid sequence of SEQ ID NO: 1; (C) the human complement factor B protein analog is at least 90% identical to amino acids 26-764 of SEQ ID NOs: 1, 2 or 3; to amino acids 26-990 of SEQ ID NOs: 22 or 23; to amino acids 26-480 of SEQ ID NO: 2; or to amino acids 26-1003 of SEQ ID NO: 26; and (D) said analog of complement factor B protein has increased binding affinity for C3b, compared to a corresponding native complement factor B protein encoded by a mammalian genome, and said analog of factor protein Complement B (i) has decreased protease activity compared to the corresponding native complement factor B protein; (ii) it has an ability to be cleaved by decreased factor D protein compared to the corresponding native complement factor B protein; or (iii) has a decreased protease activity compared to the corresponding native complement factor B protein and has an ability to be cleaved by a decreased factor D protein compared to the corresponding native complement factor B protein; or (iv) it can compete with a native factor B for binding to factor D. |