Expression and functional analysis of M_r 58000 peptides derived from the repetitive domain of high molecular weight glutenin subunit 1Dx5

A highly repetitive M_r 58000 peptide based on residues 102 to 643 of subunit 1Dx5 and forms containing one to four cysteine residues were expressed in E. coli and purified to homogeneity. Incorporation into dough using a 2 g Mixograph showed that most peptides resulted in reduced strength, which was possibly due to dilution or chain termination of glutenin polymers. However, a form containing four cysteines (two each close to the N-terminus and C-terminus) resulted in increased strength, indicating that the repetitive domains of the HMW subunits are sufficient to contribute to dough strength when incorporated into glutenin polymers.