Fusion expression and purification of HA20-lys10 in E. coli and its gel retardation experiments

Purpose: To express and purify the fused protein containing 20 residues of amino-terminal of influenza hemagglutinin HA2 and ten lysines, and investigate its ability of binding plasmid. Methods: The fused gene HA20-1ys10 containing gene of 20 residues of amino-terminal of influenza hemagglutinin HA2 and ten lysines was amplified by PCR, and was cloned into prokaryotic expression vector pET32a (+). The recombinant expression plasmid pET-HA-K was transformed into E. coli BL21 (DE3). When A600 reached 0. 6, IPTG was added to induce the expression of recombinant protein. The expressed protein was purified by one-step affinity chromatography, and its ability of binding plasmid was investigated via gel retardation experiments. Results: After induction for 3 hours by 1 mmol/L IPTG, there was a high level expression of recombinant protein, and most of them were soluble. After purification by affinity chromatography, the purity of HA20-1ys10 was up to 85%, and 20 μg HA20-1ys10 could retard plasmid completely. Conclusions: These results indicate that HA20-1ys10 is hopeful to be used in receptor-mediated gene transfer to improve the efficiency.