Efficient and Site-Specific Protein Bioconjugation Quantification in Mammalian Cells

Area of Science:

• Biochemistry
• Chemical Biology
• Molecular Biology

Background:

• Quantifying protein bioconjugation in live cells presents significant technical challenges.
• Existing methods often lack the precision or applicability for in cellulo measurements.

Purpose of the Study:

• To develop a novel, efficient, and versatile method for quantifying protein bioconjugation directly within live cells (in cellulo).
• To leverage inverse electron-demand Diels-Alder (IEDDA) cycloaddition reactions for precise biomolecule labeling and quantification.

Main Methods:

• Utilized IEDDA cycloaddition reactions to label biomolecules with unnatural amino acids (UAAs).
• Employed chloroalkane-derivatized conjugates of UAAs labeled with the HaloTag enzyme.
• Quantified bioconjugation via a gel shift assay of the conjugated protein of interest.

Main Results:

• Successfully demonstrated a new method for in cellulo quantification of protein bioconjugation.
• The method proved efficient and adaptable to various proteins of interest.
• Showcased versatility through the use of diverse UAA/bioconjugation pairs and incorporation sites.

Conclusions:

• The developed IEDDA-based method provides a robust tool for measuring protein bioconjugation in live cells.
• This technique is accessible, utilizing common laboratory instrumentation and techniques.
• Offers broad applicability for studying protein bioconjugation across different proteins and labeling strategies.