PURIFICATION OF A MAIZE DEHYDRIN PROTEIN EXPRESSED IN ESCHERICHIA-COLI

A maize dehydrin protein (Dhn1) containing 167 amino acids with a pred icted molecular weight of 17.0 kDa was produced in the Escherichia col i overexpression strain BL21(DE3)pLysS. Site-directed mutagenesis was used to construct a plasmid with a protein coding region corresponding exactly to the original cDNA Protein production was induced by IPTG. Dhn1 was enriched from total soluble protein by heat-fractionation and centrifugation and then purified by sequential cation exchange and hy drophobic interaction chromatography. The purified protein was visuali zed by SDS-PAGE and immunoblot analysis using a polyclonal antibody to the dehydrin consensus region. Expression in E. coli resulted in appr oximately 1.2 mg of purified protein per liter of induced culture. (C) 1995 Academic Press, Inc.