Designed Rubredoxin miniature in a fully artificial electron chain triggered by visible light

Area of Science:

• Protein Engineering
• Bioinorganic Chemistry
• Biophysics

Background:

• Designing metal-binding sites into de novo proteins is advancing.
• Identifying minimal coordination spheres for metal binding and activity remains challenging.

Purpose of the Study:

• To test de novo protein design principles using a challenging FeCys4 redox center.
• To create a miniature protein capable of proper folding, metal binding, and efficient electron transfer.

Main Methods:

• Assembled a 28-residue protein incorporating FeCys4 coordination.
• Determined the crystal structure of the designed tetra-thiolate protein.
• Correlated structural data with spectroscopic and electrochemical properties.

Main Results:

• Achieved sub-Ångström agreement between the designed and crystal structures.
• Demonstrated efficient electron transfer function of the designed protein.
• Observed a high reduction potential for the FeCys4 center.

Conclusions:

• The study validates de novo design strategies for creating functional metalloproteins.
• The designed protein serves as an effective terminal electron acceptor in an artificial photosynthetic system.