A BETA-TURN RICH BARLEY SEED PROTEIN IS CORRECTLY FOLDED IN ESCHERICHIA-COLI

Wild-type and cysteine-containing mutant C hordeins from barley were e xpressed in Escherichia coli at high levels (greater-than-or-equal-to 30 mg/liter). N-terminal sequence analysis, SDS-PAGE, RP-HPLC, cd spec troscopy, and small angle X-ray scattering demonstrated that their phy sicochemical properties were similar to those of C hordeins isolated f rom barley grain. This indicates that the expressed proteins were corr ectly folded. The cysteine-containing mutant showed evidence of polyme r formation in E. coli, nonreduced preparations of the protein showing the presence of polymers that were replaced by a single protein when a reducing agent was added. (C) 1994 Academic Press, Inc.