Protein Labeling and Intramolecular Cross-Arylation via Rational Tuning of Bis-Halogenated Pyridiniums

Area of Science:

• Biochemistry
• Organic Chemistry
• Chemical Biology

Background:

• Protein labeling and cross-linking are crucial for studying biomacromolecules.
• Existing methods often lack efficiency, selectivity, or biocompatibility under mild conditions.

Purpose of the Study:

• To develop efficient and selective protein arylation labeling and cross-linking strategies.
• To enable functionalization of biomacromolecules and short-chain cross-linking via nucleophile-sp2 carbon bonds.

Main Methods:

• Rational design of pyridinium platforms by modulating electronic effects and leaving groups.
• Utilizing Density Functional Theory (DFT) simulations to understand reaction mechanisms.
• Developing probes for proteome-wide labeling and bis-halogenated cross-linkers.

Main Results:

• Achieved efficient labeling and cross-linking of primary amine-containing amino acids (lysine, N-terminus) in peptides and proteins.
• DFT simulations confirmed the stabilizing effect of electron-withdrawing substituents on S_NAr pathways.
• Demonstrated global proteome-wide labeling and intramolecular lysine-cysteine cross-arylation using a bis-halogenated pyridinium cross-linker on BSA.

Conclusions:

• The developed pyridinium platforms offer a robust method for protein arylation.
• The probes enable efficient and selective modification of proteins under mild, biocompatible conditions.
• This work provides valuable tools for chemical biology and proteomics research.