From Folding Reagents to Catalysts: Spatially Organized Diselenide−Cyclodextrins Enable Catalytic Oxidative Protein Folding

Abstract

Abstract Oxidative folding, involving disulfide (SS) bond formation and isomerization, is essential for the maturation of many secreted and membrane proteins. Although numerous small-molecule mimics of protein disulfide isomerase, a key enzyme that catalyzes oxidative folding, have been developed, most require superstoichiometric amounts relative to the substrate. Here, we report cyclodextrin (CD)diselenide conjugates that create artificial folding reaction fields by spatially integrating substrate capture with redox catalysis within a topology-preserving bivalent architecture. Systematic variation of CD size, substitution pattern, and linker structure identified a γ-CDcyclic diselenide conjugate bearing two hydrophobic inclusion sites as the most effective catalyst across multiple model proteins. Mechanistic studies suggest that this bivalent architecture maintains a multivalent substrate-capture environment throughout the redox cycle, organizing protein thiols and mispaired SS bonds near the redox center to promote both SS formation and isomerization while suppressing aggregation. This reaction-field design transforms conventional folding reagents into true catalysts and establishes a molecular design principle for catalytic oxidative protein folding and the efficient production of SS-rich proteins.