Patent ID: 8633018

Claim:
An expression vector comprising a promoter and a polynucleotide sequence encoding a fusion protein; wherein the fusion protein-encoding polynucleotide sequence is so operably linked to the promoter that the transcription of the fusion protein-encoding polynucleotide sequence is controlled by the promoter; wherein the fusion protein comprises a single-stranded DNA-binding protein and an interest protein or polypeptide fused directly or indirectly with the COOH-terminus or NH 2 -terminus of the single-stranded DNA-binding protein; wherein the single-stranded DNA-binding protein is capable of binding to single-stranded DNA; and wherein the interest protein or polypeptide does not contain a physical feature that can be used for affinity purification; so that the interest protein or polypeptide can be purified as a part of the fusion protein when the fusion protein is purified by binding to single-stranded DNA via the single-stranded DNA-binding protein.