Subunit-specific interfacial adaptability of x-type HMW-GS revealed by molecular dynamics and linked to dough...

Gas-cell stability during dough fermentation depends on the ability of dough liquor (DL) proteins to adsorb and stabilize the air-water interface. However, the subunit-specific contributions of x-type high-molecular-weight glutenin subunits (HMW-GS) to this interfacial process remain unclear. Here, all-atom molecular dynamics (MD) simulations were used to examine the interfacial responses of Ax1, Bx7, and Dx2. Ax1 maintained relatively stable conformational features near the interface, Bx7 underwent moderate structural adjustments, whereas Dx2 exhibited pronounced interfacial sensitivity characterized by enhanced fluctuations and hydration-electrostatic redistribution. Consistent with these molecular differences, experimental analyses of DL extracted from fermented dough revealed that deletion of Dx2 markedly weakened interfacial performance, as reflected by reduced foaming stability, accelerated drainage, elevated surface tension, and lower interfacial viscoelasticity. These changes were accompanied by decreased ζ-potential and surface hydrophobicity, increased free -SH content, and reduced β-sheet structure, corresponding to diminished gas retention during fermentation. Together, the integrated simulation and experimental results demonstrate that subunit-dependent interfacial adaptability of x-type HMW-GS critically influences DL functionality and fermentation performance.