Abstract: The cytoplasmic domain of human erythrocyte band 3(CDB3) gene was amplified by standard PCR method from plasmid pHB3 and constructed to be a recombinant plasmid pCDBHistag with an expression vector pET28b. Recombinant CDB3 fusion protein with Polyhistidine-tag was strongly expressed as soluble protein in E coli BL21(DE3) after induction with isopropyl-β-D-thiogalactopyranoside. Affinity chromatograpy chelating with Ni ²⁺ was employed to purify the recombinant fusion CDB3 protein. About 70% of aldolase activity could be inhibited by purified recombinant CDB3 similar as the result in human erythrocyte. It suggested that aldolase could bind with the purified CDB3 fusion protein in vitro. The high-level expression and easy purification of this recombinant protein should permit thorough studies of the interaction mechanism of CDB3 with its peripheral binding proteins.

Key words: Cytoplasmic domain of band 3, Fusion protein, Affinity chromatography