Dual Hydrophilic‐Hydrophobic Core Architecture in Soy Glycinin Amyloid Fibrils Revealed by Cryo‐EM

Abstract Plant‐derived amyloid fibrils represent a promising class of sustainable nanomaterials outperforming their native counterparts in functionalities; however, the atomic‐level structural mechanisms behind these enhancements have yet to be elucidated. Using cryo‐EM, near‐atomic resolution structures (3.4 and 3.5 Å) are determined for two distinct fibril polymorphs assembled in vitro from soy glycinin‐A subunit. The dominant Type I fibril exhibits an unprecedented dual‐core architecture, characterized by spatially segregated hydrophilic (Asp172‐Asn178/Asn178’‐Asp172’) and hydrophobic (Val166‐Ile168/Val186’‐Pro184’) domains, which contribute to a unique amyloid fold distinct from many known amyloid structures, including pathological and functional amyloids. In contrast, the minor Type II fibril adopts a conventional extended hydrophobic core with Tyr155‐Tyr158 π‐stacking. These atomic structures establish fundamental structure‐property relationships that will inform the rational design of plant protein‐based nanomaterials.