CONSTRUCTION OF NOVEL WHEAT HIGH-M(R) GLUTENIN SUBUNIT GENE VARIABILITY - MODIFICATION OF THE REPETITIVE DOMAIN AND EXPRESSION IN ESCHERICHIA-COLI

We report the construction of modified high M(r) glutenin subunit gene s with variable lengths of the repetitive domain and their expression in Escherichia coli. The modified glutenin subunits showed anomalously slow migration by SDS-PAGE characteristic of these polypeptides. Chan ges in the size of the repetitive domain correlated with both the migr ation behaviour on SDS-PAGE and with the surface hydrophobicities of t he polypeptides measured by RP-HPLC. These constructs made it possible to obtain direct evidence for the first time that the anomalous elect rophoretic mobilities of high M(r) glutenin subunits in SDS-PAGE, comp ared with globular proteins, are mainly due to the repetitive domain. These constructs should be useful for establishing the role of the rep etitive domain of high,I, glutenin subunits in determining the viscoel astic properties of dough. They also offer the possibility of creating new genetic variability For wheat improvement. (C) 1997 Academic Pres s Limited