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Forskningsartikel2022Vetenskapligt granskadÖppen tillgång

Clustering and cross-linking of the wheat storage protein ?-gliadin: A combined experimental and theoretical approach

Markgren, Joel; Rasheed, Faiza; Hedenqvist, Mikael S.; Skepo, Marie; Johansson, Eva

Sammanfattning

Our aim was to understand mechanisms for clustering and cross-linking of gliadins, a wheat seed storage protein type, monomeric in native state, but incorporated in network while processed. The mechanisms were studied utilizing spectroscopy and high-performance liquid chromatography on a gliadin-rich fraction, in vitro produced alpha-gliadins, and synthetic gliadin peptides, and by coarse-grained modelling, Monte Carlo simulations and prediction algorithms. In solution, gliadins with alpha-helix structures (dip at 205 nm in CD) were primarily present as monomeric molecules and clusters of gliadins (peaks at 650- and 700-s on SE-HPLC). At drying, large polymers (Rg 90.3 nm by DLS) were formed and 13-sheets increased (14% by FTIR). Trained algorithms predicted aggregation areas at amino acids 115-140, 150-179, and 250-268, and induction of liquid-liquid phase separation at P- and Poly-Q-sequences (Score = 1). Simulations showed that gliadins formed polymers by tail-to-tail or a hydrophobic core (Kratky plots and Ree = 35 and 60 for C- and N-terminal). Thus, the N-terminal formed clusters while the C-terminal formed aggregates by disulphide and lanthionine bonds, with favoured hydrophobic clustering of similar/exact peptide sections (synthetic peptide mixtures on SE-HPLC). Mechanisms of clustering and cross-linking of the gliadins presented here, contribute ability to tailor processing results, using these proteins.

Nyckelord

Disulphide bonds; Monte Carlo simulations; Polymers; Synthetic peptides

Publicerad i

International Journal of Biological Macromolecules
2022, Volym: 211, sidor: 592-615
Utgivare: ELSEVIER