Multisite clickable modification of proteins using lipoic acid ligase

Area of Science:

• Biochemistry
• Chemical Biology
• Protein Engineering

Background:

• Site-specific protein modification is crucial for modulating protein activity and stability.
• Existing methods struggle with site-selective modification at multiple, including internal, protein positions.

Purpose of the Study:

• To develop an enzymatic approach for multisite clickable protein modification.
• To enable site-selective incorporation of azide moieties at multiple protein sites.

Main Methods:

• Utilized lipoic acid ligase (LplA) for enzymatic ligation of azide moieties to proteins.
• Employed green fluorescent protein (GFP) as a model system for N-terminal and internal site modification.
• Performed bioorthogonal click chemistry for conjugation with PEG, sugars, and fatty acids.

Main Results:

• Achieved efficient, near-complete incorporation of azide moieties at N-terminal and internal sites of GFP.
• Generated highly homogeneous protein conjugates (protein-polymer, protein-sugar, protein-fatty acid).
• Demonstrated rapid ( < 30 min) and homogeneous PEGylation of GFP using click chemistry and successful protein immobilization.

Conclusions:

• The LplA-based enzymatic approach enables efficient multisite, site-specific protein modification.
• This method yields homogeneous protein conjugates for applications like PEGylation, glycosylation, and immobilization.
• The developed technique overcomes limitations of previous methods for complex protein labeling.