Nanoparticle Shape-Templated Peptide Organization Enables Tunable Enhancement of Enzyme Activity.

Abstract

Biological systems often regulate catalysis by organizing enzymes within dense, multivalent, and nanostructured environments. Nanomaterials can recreate selected features of these environments, but their effects on enzymes range from inhibition to activity enhancement depending on the chemistry of their surface ligands. Here, we show that the same surface ligand can produce dramatically different catalytic outcomes when templated onto distinct nanoparticle geometries. Inspired by peptide- and protein-rich biological environments, we displayed a short peptide ligand as a dense, multivalent array on gold nanoparticles with 10 distinct architectures, including spheres of different diameters, nanocubes, nanorods, nanobipyramids, and nanostars with varying branching densities. Using lactoperoxidase as a model enzyme, we found that all peptide-functionalized nanoparticles enhanced activity relative to free lactoperoxidase, but the magnitude of enhancement depended strongly on particle morphology, ranging from ∼1.8-fold on nanocubes to ∼11.3-fold on highly branched nanostars. Mechanistic studies showed that these differences could not be explained solely by enzyme binding affinity or substrate enrichment. Instead, kinetic analysis, circular dichroism spectroscopy, mixed-ligand experiments, and peptide-loading comparisons support a model in which nanoparticle surfaces template distinct peptide arrangements that induce controlled enzyme perturbations and increase apparent catalytic turnover. To show the importance of the displayed peptide ligand on enzyme regulation, we translated the enhancing peptide motif to silica nanoparticles. These peptide-functionalized silica nanoparticles also increased lactoperoxidase activity, and additionally improved thermal stability. Together, these findings establish nanoparticle-templated peptide presentation as a programmable, core-translatable strategy for tuning enzyme activity and stability.