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Synthesis and Bioconjugation of Thiol-Reactive Reagents for the Creation of Site-Selectively Modified Immunoconjugates
Published on: March 6, 2019
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The Nitrile Bis-Thiol Bioconjugation Reaction
Mikesh Patel1, Nafsika Forte1, Charlie R Bishop1
1Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K.
Journal of the American Chemical Society
|December 21, 2023
Summary
Researchers developed a new "nitrile bis-thiol" (NBT) reaction for stable bioconjugation. This click-type reaction efficiently modifies antibody proteins at specific sites, offering a versatile new tool for bioconjugation protocols.
Area of Science:
- Bioconjugation Chemistry
- Organic Synthesis
- Protein Modification
Background:
- Electron-poor aryl nitriles react with thiols but typically form reversible adducts.
- A transient tetrahedral amino dithioacetal (ADTA) intermediate is observed in these reactions.
- Stable ADTAs are desired for developing new bioconjugation strategies.
Purpose of the Study:
- To explore the reaction of heteroaryl nitriles with bis-thiols to generate stable ADTAs.
- To develop novel bioconjugation protocols using these stable adducts.
- To investigate the application of this reaction in protein and antibody modification.
Main Methods:
- Utilized 1,2-dithiols or electrophilic traps to stabilize ADTA formation.
- Developed the "nitrile bis-thiol" (NBT) reaction.
- Applied NBT reagents to antibody fragments and full antibodies, targeting reduced disulfide bonds.
Main Results:
- Achieved formation of stable ADTAs through specific reagent design.
- Demonstrated site-selective antibody fragment conjugation, yielding cysteine-to-lysine transfer or disulfide-bridged NBT products.
- Confirmed stability of conjugates under physiological conditions and serum incubation.
- Successfully modified all four disulfide bonds in a full antibody using NBT reagents.
Conclusions:
- The reaction of heteroaryl nitriles with bis-thiols provides a highly efficient and versatile method for generating stable bioconjugates.
- The NBT reaction offers tunable reversibility and is a promising biocompatible click-type reaction for protein and antibody modification.
- This new reaction expands the toolbox for developing advanced bioconjugation strategies.
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