SpyCatcher-Multiplicity Tunes Nanoscaffold Hydrogels for Enhanced Catalysis of Regulated Enzymes

This study presents a strategy for enhancing hydrogel formation through SpyCatcher-mediated conjugation of nanoscale scaffold proteins. We demonstrate that SpyCatcher can facilitate hydrogel assembly with various nano-scaffolds of diverse structural configurations. By conjugating one, two, or three SpyCatcher units to the P9 protein nanoscaffold, hydrogel yield was substantially increased, allowing for the simultaneous co-immobilization of a larger number of enzymes. Characterization using cell-free biosynthesis, electron microscopy, and rheological analysis revealed that the resulting SpyCatcher-mediated nanoscaffold hydrogels exhibit soft solid-like behavior, high elasticity, and an “ink-bottle” pore morphology, which collectively promote and regulate enzymatic activity. Notably, hydrogels crosslinked via the P9 scaffold with two SpyCatcher units showed the most balanced properties, leading to a 149% increase in pyruvic acid production. These findings not only advance the efficient design of hydrogels for enzyme co-immobilization but also provide a foundation for developing more sophisticated models and expanding the scope of biocatalytic systems.