Designer Heme Proteins: Achieving Novel Function with Abiological Heme Analogues

Area of Science:

• Biochemistry and Biotechnology
• Protein Engineering
• Biomedical Applications

Background:

• Heme proteins serve as versatile platforms for engineering novel protein functions.
• Substitution of the native heme cofactor with analogues offers a route to new protein properties.
• Existing methods for cofactor substitution can lead to protein denaturation and loss.

Purpose of the Study:

• To develop improved methods for incorporating artificial cofactors into heme proteins.
• To engineer designer heme proteins for diverse applications in health and medicine.
• To leverage stable heme proteins as scaffolds for advanced biomedical tools.

Main Methods:

• Utilizing a modified *E. coli* strain (RP523) for heme-biosynthesis deficient growth.
• Supplementing growth media with artificial heme analogues for direct incorporation into heme proteins.
• Employing expression-based methods for reconstituting apoproteins with non-native cofactors.

Main Results:

• Successfully incorporated various artificial cofactors into stable heme proteins like H-NOX and HasA.
• Developed designer proteins for optical oxygen sensing, MRI contrast agents, and fluorescent probes.
• Demonstrated antibacterial activity and photochemical sterilization using engineered HasA proteins.

Conclusions:

• Expression-based incorporation of artificial cofactors offers a robust alternative to traditional reconstitution methods.
• Designer heme proteins exhibit significant potential for next-generation biomedical sensing, imaging, and therapeutic applications.
• Engineered heme proteins can address critical challenges in disease diagnosis and treatment.