Human monocyte chemoattractant protein-1 (hMCP-1) is one of the main chemokines that controls the migration and infiltration of monocytes and lymphocytes. Both hMCP-1 and its receptor are involved in various diseases, including atherosclerosis, cancer, and rheumatoid arthritis. Therefore, recombinant hMCP-1 (rhMCP-1) can be used to help develop therapeutic modulators of these diseases. However, rhMCP-1 often exists as an inclusion body in Escherichia coli expression systems and commercially available rhMCP-1 is expensive. In our current study, a 228-bp gene that encodes hMCP-1 was synthesized. Codon usage was optimized to include the codons used in highly expressed E. coli genes. The synthetic hMCP-1 gene was cloned into ap ET SUMO (small ubiquitin-like modifier) vector and overexpressed in E. coli as anintact, soluble protein. Because rhMCP-1 was easily solubilized, no furthersolubilization steps were needed for purification and no additional tagging residues were introduced into the rhMCP-1 gene product. Our purified rhMCP-1 demonstrated similar chemotactic properties and molecular weight as commercially available rhMCP-1. Hence, our SUMO fusion system is a promising and efficient approach for scaling-up the soluble expression of rhMCP-1.
