Zinc Fingers as Programmable Metalloprotein Scaffolds for Altering Pathogenic Biomolecular Phase Transitions.

Tunable control over biomolecular phase transitions provides a powerful blueprint for engineering functional soft materials, yet generalizable protein scaffolds capable of rewiring pathological condensates remain largely unexplored. Here, we demonstrate that zinc finger (ZF) proteins function as programmable interaction units that modulate neurodegenerative amyloid liquid-liquid phase separation, redirect β-sheet-rich fibrillation toward nontoxic assemblies, and actively disassemble preformed fibrils. Multiscale investigations spanning molecular, cellular, and organismal levels reveal that tandemly arrayed ZF modules mediate direct, high-affinity protein-protein interactions, thereby mitigating amyloid pathogenicity. Through modular protein engineering, these protective effects translate in vivo, where a brain-penetrant ZF variant reduces amyloid deposition, suppresses neuroinflammatory responses, and improves cognitive performance in Alzheimer's disease transgenic mice. Furthermore, sequence-structure-function analyses identify key determinants governing amyloid assembly control, offering mechanistic principles for ZF-inspired protein engineering. Collectively, this work positions ZF proteins as versatile, chemically programmable platforms for engineering protein-based materials that regulate biomolecular phase behavior and toxicity, expanding their functional scope beyond traditional genetic regulation toward therapeutic applications.