BIOCHEMICAL STUDIES OF CEREAL PROLAMINS FROM SORGHUM AND WHEAT by

Prolamins are the alcohol soluble storage proteins found in the endosperm of seeds from cereals and related grasses. The physical and biochemical properties of prolamins vary between species; and due to their relative abundance can greatly affect the properties and healthfulness of foods from those sources. In this work I investigate peptides from the high molecular weight glutenin of wheat, which is linked to dough elasticity and finished product quality. Using 2D NMR I determined the three-dimensional structure for the repeat peptide Ac-GQQPGQG-Am, which makes up ~50 % of the 700 residue central domain. The structure was found to be a flexible β-hairpin with a type II β-turn across residues QPGQ. The NMR structure was later compared to 33 proteins with known three-dimensional structure carrying the exact sequence (backbone RMSD=0.802Å). This finding provides useful insight into the structure of high molecular weight glutenin and the molecular nature gluten elasticity. Alternatively, I studied the kafirin storage prolamins from sorghum, which do not have important physical properties, but are poorly digestible by humans and livestock. Improving digestibility of sorghum could significantly impact human health and nutrition in countries wher