Related Experiment Video
Updated: May 14, 2026
09:14
Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry
Published on: July 20, 2016
41.2K
Mechanistic Insights into Chemoselective Reduction of Engineered Cysteine Residues in Antibodies Using Computational
Manish Hudlikar1, Jingzhou Wang1, Xingjian Yu1
1Discovery Chemistry, Merck & Co., Inc., 213 E Grand Ave, South San Francisco, California 94080, United States.
Journal of the American Chemical Society
|April 8, 2026
Summary
This study reveals principles for designing selective phosphine reductants for antibody-drug conjugates (ADCs). New reagents enable site-specific conjugation and the creation of dual-payload ADCs without complex linkers.
Area of Science:
- Bioconjugation Chemistry
- Protein Engineering
- Computational Chemistry
Background:
- Site-specific antibody-drug conjugates (ADCs) offer advantages over conventional ADCs.
- Chemoselective reduction of engineered cysteines using phosphine reductants is not well understood.
Purpose of the Study:
- Elucidate the mechanism of selective reduction for engineered cysteine residues.
- Develop principles for designing novel chemoselective phosphine reductants.
- Enable sequential conjugation for homogeneous dual-payload ADCs.
Main Methods:
- Integrated experimental screening and computational modeling.
- Developed a two-factor computational framework (accessibility and TS1 activation barrier).
- Tested reductants on engineered cysteine sites (S375C and S168C) on IgG1.
Main Results:
- The computational framework successfully rationalized reductant selectivity.
- New phosphine reagents with improved chemoselectivity were developed.
- Demonstrated sequential conjugation for dual-payload ADCs without complex linkers.
Conclusions:
- Provided broadly applicable guidance for phosphine selection and design.
- Achieved chemoselective, site-specific antibody conjugation.
- Enabled the creation of homogeneous dual-payload ADCs through sequential conjugation.
