Histidine Containing Minimalistic-Peptide-Based Nanostructured Hydrogel for Multiple Enzyme-Mimicking Catalytic...

The exceptional catalytic prowess of native enzymes is inherited from their ability to fold into distinctive arrangements with appropriate positioning of the amino acid constituents. Thanks to their selective and efficacious catalytic competence, enzymes play a critical role in industry and academic research. Yet their practical implementations are substantially impeded because of their low stability, complicated recovery, and expensive and exhaustive production. Peptide hydrogels with organized assemblies not only structurally recapitulate enzymes but also offer additional advantages, including excellent reusability and easy separation due to their semisolid nature. Herein, a minimalistic dipeptide, comprising catalytically active histidine is conceived that produces a nanostructured hydrogel with excellent hydrolase mimicking aptitude. The gelation and substrate binding mechanisms are deciphered from molecular dynamics simulations. Furthermore, metal ion cofactors are incorporated into the peptide hydrogel to mimic metalloenzymes. The peptide/Zn²⁺ hydrogel catalyzed the hydrolysis of CO₂, substantiating its ability to mimic the active center of carbonic anhydrase. Likewise, the peptide/Cu²⁺ hydrogel, imitating the active center of laccase, catalyzed the oxidation of toxic phenolic compounds and biologically relevant catecholamines. This work exemplifies the utilization of a single hydrogel for versatile catalytic ability, leading to its potential applications in the chemical industry, environmental remediation, and biomedical research.