Investigating the molecular mechanism of high-molecular-weight glutenin subunit affects gluten aggregation during dough mixing: Experimental characterizations and computational simulations

Abstract

This study investigated the impact of high-molecular-weight glutenin subunits (HMW-GS) on gluten aggregation and dough rheology at different mixing stages, using wheat lines with deletions at the Glu-B1 locus. Dough rheology was analyzed across varying mixing levels, while the multiscale structure and composition of gluten were systematically characterized. Additionally, molecular dynamics simulations under increased pressure (10 bar) provided detailed insights into the structural dynamics of different HMW-GSs. The results showed that optimum mixing promoted gluten aggregation, enhancing viscoelasticity, while over-mixing led to disaggregation. HMW-GS deletions, particularly of Bx7, significantly hindered gluten aggregation under optimum mixing, limiting stable disulfide bonds, intermolecular β-sheet formation, and hydrophobic interactions essential for tertiary structure. Conversely, HMW-GS deletions facilitated disaggregation during over-mixing, with Bx7 deletion having a stronger impact. Molecular dynamics simulations further illustrated Bx7's role, showing its more hydrophobic and flexible structure compared to By8, supporting the experimental observation that Bx7 deletion affects gluten network integrity more markedly. These findings underscore the critical role of HMW-GS in modulating gluten aggregation, providing a molecular basis for targeted HMW-GS manipulation in wheat breeding to enhance dough functionality and improve processing stability across various mixing conditions.