Site-Selective Protein Conjugation by a Multicomponent Ugi Reaction

Area of Science:

• Chemical Biology
• Protein Engineering
• Medicinal Chemistry

Background:

• Chemical bioconjugation is vital for antibody-drug conjugates (ADCs) in oncology.
• Modifying native proteins selectively remains challenging, especially for larger proteins.
• Existing methods often lack site-selectivity, limiting precise protein modification.

Purpose of the Study:

• To investigate the Ugi multicomponent reaction for site-selective protein conjugation.
• To develop conditions for modifying amine and carboxylate groups on antibodies.
• To assess the impact of this strategy on antibody affinity and ADC potency.

Main Methods:

• Application of the Ugi multicomponent reaction for protein modification.
• Mechanistic studies and peptide mapping to optimize reaction conditions.
• Site-selective conjugation of N-terminal glutamate and aspartate residues on antibodies.

Main Results:

• Developed conditions for highly selective antibody modification.
• Demonstrated preservation of antibody affinity for target antigens.
• Successfully produced an antibody-drug conjugate with subnanomolar potency.
• Showcased maintained site selectivity in other protein formats like anticalins.

Conclusions:

• The Ugi reaction offers a powerful tool for site-selective protein bioconjugation.
• This method enables precise modification of antibodies without compromising function.
• The strategy is applicable to various protein formats, including anticalins.