Patent ID: 7094548

Claim:
A polypeptide for use in purifying a target peptide, said polypeptide comprising the sequence X 20 -(X 1 -Y-K-X 2 -X 3 -D-X 4 ) n -X 5 -(X 1 -Y-K-X 7 -X 8 -D-X 9 -K)-X 21 where: D, Y and K are their representative amino acids; X 20 and X 21 are independently hydrogen or a bond; each X 1 and X 4 is independently a bond or at least one amino acid residue selected from the group consisting of naturally occurring aromatic amino acid residues and naturally occurring hydrophilic amino acid residues; each X 2 , X 3 , X 7 and X 8 is independently an amino acid residue selected from the group consisting of naturally occurring aromatic amino acid residues and naturally occurring hydrophilic amino acid residues; X 5 is a bond, resulting in the linking sequence being immediately adjacent to said multiple copies of the antigenic domain, or a spacer domain, said spacer domain comprising at least one naturally occurring amino acid residue or a combination of multiple or alternating histidine residues, said combination comprising His-Gly-His, or —(His—X) m —, wherein m is 1 to 6 and X is selected from the group consisting of Gly, His, Tyr, Trp, Val, Leu, Ser, Lys, Phe, Met, Ala, Glu, Ile, Thr, Asp, Asn, Gln, Arg, Cys, and Pro; X 9 is a bond or an aspartate residue; and n is at least 2.