Artificial β-propeller protein-based hydrolases

Area of Science:

• Biochemistry
• Protein Engineering
• Catalysis

Background:

• Artificial enzymes offer tailored catalytic functions.
• Protein scaffolds provide robust frameworks for enzyme design.
• Metal-free hydrolysis is desirable for green chemistry applications.

Purpose of the Study:

• To develop a novel artificial hydrolase based on the Pizza6 beta-propeller protein.
• To investigate the catalytic mechanism and optimize activity through site-specific mutagenesis.
• To explore the potential applications of the artificial enzyme in various chemical fields.

Main Methods:

• Protein engineering of the Pizza6 beta-propeller scaffold.
• Site-specific mutagenesis to introduce catalytic residues.
• Crystallisation studies to determine enzyme structure.
• Enzyme kinetics assays to measure catalytic efficiency (kcat).

Main Results:

• An artificial hydrolase was successfully developed for metal-free hydrolysis.
• The catalytic mechanism was elucidated, involving a threonine-histidine dyad.
• A mutant forming a His-His-Thr triad exhibited significantly enhanced kcat values.
• The performance of the engineered enzyme rivaled that of metalloenzymes.

Conclusions:

• The symmetrical Pizza6 beta-propeller serves as an effective scaffold for artificial hydrolase design.
• Site-specific mutagenesis can precisely tune catalytic activity and mechanism.
• The developed artificial enzyme shows promise for bioinorganic chemistry, supramolecular chemistry, and catalytic materials.