Cysteine-containing peptides are produced by sequential clipping, but not released, from lupin 11S storage globulin during early germination

Abstract

The digestion of the seed storage proteins is a finely regulated process operated by several proteases whose action is influenced by the exposure of specific regions, which became progressively available upon their action. We focused our study on the initial stages of germination, where more subtle modifications to the storage proteins are expected. Small-size peptides containing cysteine residues and other possible metalbinding regions are de facto produced but are not released from the “parental” protein since they remain bound trough disulphide bridges. The meaning of these findings is discussed.

Thermal Shift Assay as a Tool to Evaluate the Release of Breakdown Peptides from Cowpea β-Vignin during Seed Germination

“…Once we determined the pH and ionic strength conditions at which β-vignin showed maximum stability in solution, we decided to investigate its attitude to oligomerization using a size exclusion chromatography (SEC) approach to shed light on β-vignin monomer to trimer transition as a function of the pH. As a matter of fact, the correlation between pH and oligomerization of seed globulins has been already observed [ 16 , 20 ]. The results are shown in Figure 4 .…”

“…We undertook the present study as part of our research activity aimed to characterize the molecular relationships between structure and function of seed storage proteins [ 14 , 15 , 16 , 17 ]. The molecular characterization of β-vignin was carried out firstly by assessing its thermal stability, under different conditions of pH and ionic strength, using TSA.…”