[Expression of osteopontin RGD peptide in E. coli and its biological activities]

The six copies of RGD sequences present in osteopontin were expressed in the E. coli, and the biological activity of the purified products was studied.

cDNA fragments containing six copies of RGD sequences were subcloned into prokaryotic expression vector pGEX-3X including GST coding sequence to construct pGEX-3X-RGD plasmids. E. coli DH5alpha transformed by pGEX-3X-RGD(6) plasmid was induced by different IPTG concentrations for different times to identify the optimal induction condition. Induced GST-RGD fusion protein was purified via GST-Sepharose 4B affinity resin.

GST-RGD fusion proteins containing six copies of RGD sequences could be successfully induced and were mainly located in inclusion bodies. After being denatured and dialyzed, renatured fusion proteins were purified via GST-Sepharose 4B affinity resin. GST-RGD(6) fusion protein could specifically inhibit adhesion and migration of VSMC stimulated by osteopontin, which could be considered as a basis on producing small peptides containing RGD sequences for inhibition of VSMC adhesion and migration.

The six copies of osteopontin RGD peptide were successfully expressed in E. coli DH5alpha. The purified GST-RGD fusion protein could inhibit the adhesion and migration of VSMC stimulated by osteopontin.