Heterologous expression and dough mixing studies of a novel cysteine-rich avenin-like protein

The Avenin-like gene (EU096532) was cloned from Aegilops biuncialis (2n = 4X, UUMM) in our previously study, the encoded gluten protein contained 19 cysteine residues, much more than that in all other glutenin subunits characterized so far. In present study, the protein was expressed in E. coli in large scale and purified in high purity through His-binding affinity chromatography. The purified protein was simply added or incorporated into a base flour and conducted with a 2 g Mixograph in order to investigate the functional properties including mixing time (MT), peak dough resistance (PR) and breakdown in resistance (RBD). Both 10 mg and 15 mg Avenin-like protein could cause significant increases in MT and PR, and decrease in RBD, compared to the control, when incorporated into dough. But the latter showed larger effect on functional properties. Size exclusion high-performance liquid chromatography (SE-HPLC) analysis confirmed that Avenin-like protein was chemically incorporated into polymeric subunits by intermolecular disulphide bonds