Glutenin and Gliadin, a Piece in the Puzzle of their Structural Properties in the Cell Described through Monte Carlo Simulations

Abstract

Gluten protein crosslinking is a predetermined process where specific intra- and intermolecular disulfide bonds differ depending on the protein and cysteine motif. In this article, all-atom Monte Carlo simulations were used to understand the formation of disulfide bonds in gliadins and low molecular weight glutenin subunits (LMW-GS). The two intrinsically disordered proteins appeared to contain mostly turns and loops and showed “self-avoiding walk” behavior in water. Cysteine residues involved in intramolecular disulfide bonds were located next to hydrophobic peptide sections in the primary sequence. Hydrophobicity of neighboring peptide sections, synthesis chronology, and amino acid chain flexibility were identified as important factors in securing the specificity of intramolecular disulfide bonds formed directly after synthesis. The two LMW-GS cysteine residues that form intermolecular disulfide bonds were positioned next to peptide sections of lower hydrophobicity, and these cysteine residues are more exposed to the cytosolic conditions, which influence the crosslinking behavior. In addition, coarse-grained Monte Carlo simulations revealed that the protein folding is independent of ionic strength. The potential molecular behavior associated with disulfide bonds, as reported here, increases the biological understanding of seed storage protein function and provides opportunities to tailor their functional properties for different applications.

New exploration of the γ-gliadin structure through its partial hydrolysis

“…The low charge content of γ gliadin and its truncated domains suggests that they belong to the weak polyelectrolytes/polyampholytes category which could adopt globules or tadpoles conformations (compact con formation) [37]. Similar results were recently obtained for α gliadin and low molecular weight glutenin [35]. Besides, the composition anal ysis of γ gliadin amino acid sequence suggests a significant enrichment in proline and glutamine as compared to other IDPs (see Supplementary Fig.…”

Title: Characterization of gliadin, secalin and hordein using advance analytical techniques

“…Gliadin showed monomeric units nonetheless hordein shows the existence of some higher ordered aggregates. This fact is also supported by amino acid composition that the higher proportion of basic AA and S-containing AA residues in hordein shows its tendency in formation of aggregates through strong electrostatic and hydrostatic interaction 9 . The secalin showed a bimodal PSD with two populations in the solution.…”

“…The inter-planar spacing, 'd', was calculated from the peak positions using Bragg's equation ( 9 reported that α-gliadin and LMW-GS showed a similar secondary structure propensity in the absence of intra-molecular disulphide bonds with a relatively uniform distribution of α-helix and/or β-sheet whereas when intra-molecular disul de bonds are involved there is an increased tendency for β-sheet/strand for the amino acid involved in these speci c bonds. It can be inferred from the previous study that the prolamins under investigation also had α-helix and/or β-strand structures.…”

“…These periodic regular arrangements probably attributed to the subsistence of β-sheet structure among the prolamin and disulphide bonding as a result of intra-molecular interaction which mainly involves cysteine residues in polypeptide chains 50 . Markgren et al, 9 highlighted the role of cysteine amino acid in intra-molecular disulphide bonding, which when located in more hydrophobic motif and stated that the intra-molecular interaction enhances the tendency of formation of more ordered β-sheet con guration. Similarly, 51 also reported the crystalline structure of proteins by XRD studies and attributed it to the βsheet structure.…”

“…Numerous protocols are available for the extraction of prolamin but only a few could extract the prolamin without glutenin cross contamination especially with LMW-glutenin sub unit due to their similar genetic characteristics and trapping of prolamin in the glutenin polymeric network via disulphide linkages 9 . Fu & Kovacs, 10 reported a prolamin extraction protocol which was modi ed by 11 , for claiming the complete extraction of prolamin, free from glutenin cross contamination, with short i.e.…”