Site-specific chemical protein conjugation using genetically encoded aldehyde tags

Area of Science:

• Biochemistry
• Molecular Biology
• Protein Engineering

Background:

• Site-specific protein modification is crucial for developing advanced bioconjugates.
• Existing methods often lack efficiency or specificity.
• Chemoenzymatic approaches offer a promising alternative for precise protein functionalization.

Purpose of the Study:

• To develop and present a robust chemoenzymatic method for site-specific protein modification.
• To demonstrate the utility of formylglycine generating enzyme (FGE) for creating aldehyde tags in recombinant proteins.
• To establish a protocol for generating, analyzing, and conjugating modified proteins.

Main Methods:

• Utilizing formylglycine generating enzyme (FGE) to recognize and oxidize a specific pentapeptide sequence (CxPxR) in recombinant proteins.
• Inserting the FGE recognition sequence (aldehyde tag) into heterologous proteins expressed in prokaryotic or eukaryotic systems.
• Co-overexpressing FGE with the target protein to generate formylglycine, which is then reacted with α-nucleophiles for bioconjugation.

Main Results:

• Successfully generated aldehyde-tagged proteins at specific termini using the FGE system.
• Demonstrated selective chemical conjugation to the formylglycine residue with α-nucleophiles.
• The entire process, from protein generation to purification, can be completed within 20 days.

Conclusions:

• The described chemoenzymatic bioconjugation method provides a versatile and efficient means for site-specific protein modification.
• This technique facilitates the creation of precisely engineered bioconjugates for various applications.
• The protocol is applicable to both prokaryotic and eukaryotic expression systems, enhancing its broad utility.