Live-Cell Protein Modification by Boronate-Assisted Hydroxamic Acid Catalysis

Area of Science:

• Chemical Biology
• Biochemistry
• Synthetic Chemistry

Background:

• Selective protein post-translational modifications (PTMs) are crucial for understanding biological functions.
• Existing enzymatic methods limit the diversity of accessible PTMs.
• Abiotic catalysis offers a route to novel, non-natural PTMs.

Purpose of the Study:

• To develop a novel abiotic catalyst for selective protein modification in living cells.
• To overcome limitations of existing methods, such as glutathione sensitivity.
• To demonstrate the utility of boronic acid-diol complexation in bio-orthogonal chemistry.

Main Methods:

• Development of the boronate-assisted hydroxamic acid (BAHA) catalyst system.
• Utilizing a local molarity effect for efficient acyl transfer to lysine residues.
• Testing catalyst resistance to glutathione and off-target reactivity.

Main Results:

• The BAHA catalyst system demonstrated selective acylation of target lysine residues.
• The catalyst functions effectively at low micromolar reagent concentrations.
• BAHA exhibited resistance to glutathione, a common biological interferent.
• Successful installation of various acyl groups onto *E. coli* dihydrofolate reductase in human cells.

Conclusions:

• The BAHA catalyst system provides a robust method for introducing diverse acyl groups onto proteins in living cells.
• Boronic acid-diol complexation is validated as a bio-orthogonal reaction for in-cell applications.
• This methodology expands the toolkit for chemical biology and in-cell catalysis.