Protein disulfide bonds and thiol groups are central structural elements that strongly influence the quality of food products and raw materials. For example, disulfide bond formation in gluten proteins is critical for wheat dough rheological properties in baking. In malting, a protein disulfide reductase, thioredoxin, acts on specific barley protein disulfide bonds. The global action of thioredoxin in germinating barley seeds is monitored by proteoome analysis and oxidised thioredoxin is regenerated using NADPH dependent thioredoxin reductase. Quantitative proteomics using mass spectrometry can identify the spatio-temporal reduction of thioredoxin target disulfides. This can be correlated with expression profiles of genes encoding target proteins and thioredoxin reductases. By solving the three dimensional structure of thioredoxin in complex with a target protein we identified structural motifs for recognition of target proteins by thioredoxin. This information can be combined with bioinformatic analysis for prediction of target proteins in proteomes.
For detailed project information, please contact Professor Birte Svensson (), Associate Professor Per Hägglund () or Associate Professor Christine Finnie ().
Figure 1. The thioredoxin system. Thioredoxin (SH2) reduces disulfide bonds (S2) in target proteins. Oxidized thioredoxin (S2) is reduced by thioredoxin reductase, which receives reducing equivalents from NADPH
Figure 2. Barley thioredoxin h (HvTrxh2) in a disulfide linked complex with barley a-amylase subtilisin inhibitor (BASI). A) Overview showing the secondary structure of the two proteins and the contact area in transparent gray. B) Close-up view showing the interactions in the protein-protein interface.