Combining Rational Design and Continuous Evolution on Minimalist Proteins That Target the E-box DNA Site

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• Protein-based therapeutics are emerging as a new class of drugs targeting oncogenic proteins.
• The proto-oncoprotein Myc plays a critical role in cancer development.
• Targeting Myc's interaction with DNA via the E-box motif is a promising therapeutic strategy.

Purpose of the Study:

• To design and develop a novel protein therapeutic, MEF, targeting the Myc-Max complex.
• To enhance the DNA-binding affinity and specificity of a previously developed inhibitor.
• To leverage a combination of rational design and directed evolution for protein drug development.

Main Methods:

• Rational design of a hybrid protein (ME47) combining Max basic region and E47 helix-loop-helix.
• Phage-assisted continuous evolution (PACE) to introduce stabilizing mutations.
• Protein engineering to enhance dimerization and DNA-binding activity, creating the MEF protein.

Main Results:

• MEF exhibits a 2-fold increase in binding affinity to the E-box motif compared to ME47.
• MEF shows a 4-fold improvement in specificity for E-box over non-specific DNA sequences.
• Mutations identified via PACE enhanced the stability of the protein.

Conclusions:

• The engineered protein MEF demonstrates superior DNA-binding properties for targeting Myc.
• The combined approach of rational design and PACE is effective for developing robust protein therapeutics.
• MEF represents a promising candidate for next-generation cancer therapies targeting Myc.