Biological Activity of Brain-derived Neurotrophic Factor with Mismatched Disulfide Linkages Produced by Escherichia coli

Abstract

E. coli cells harboring an expression plasmid with a brain-derived neurotrophic factor (BDNF) gene obtained from rat BDNF cDNA were sonicated and centrifuged to obtain a precipitate containing BDNF. Ten different proteins of BDNF were purified from the precipitate and the three disulfide linkages of six proteins were identified. Those disulfide structures were different from that of authentic BDNF and the biological activities of BDNF with mismatched disulfide linkages (EC₅₀ of 2 to 15ng/ml) were much lower than that of authentic BDNF (EC₅₀ of 30 pg/ml). The BDNF with mismatched disulfide linkages inhibited the biological activity of authentic BDNF.