GATS tag system is compatible with biotin labelling methods for protein analysis.

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Biology

Background:

• Polypeptide tags and biotin labeling are crucial for protein analysis.
• Lysine residues in conventional tags can be masked by biotinylation, reducing sensitivity.
• Existing methods face limitations in sensitivity and specificity due to tag design.

Purpose of the Study:

• To develop a novel polypeptide tag system free of lysine residues.
• To enhance sensitivity and reduce non-specific binding in protein analysis techniques.
• To improve biotin labeling methods, including BioID and NHS-Sulfo-biotin.

Main Methods:

• Development of the GATS tag system using a rabbit monoclonal antibody against Plasmodium falciparum glycosylphosphatidylinositol (GPI)-anchored micronemal antigen (PfGAMA).
• Selection of a specific antibody clone (Ra3) recognizing a lysine-free epitope (TLSVGVQNTF).
• Characterization using surface plasmon resonance, immunoblotting, immunoprecipitation, and immunostaining.

Main Results:

• The GATS tag system demonstrated high affinity (8.71 × 10⁻⁹ M) and a lysine-free epitope.
• Highly sensitive and specific detection with very low background in immunoblotting of mammalian cell lysates.
• Effective application in immunoprecipitation and immunostaining of human cells.
• Superior sensitivity in biotin labeling methods (NHS-Sulfo-biotin and BioID) compared to lysine-containing tags.

Conclusions:

• The GATS tag system offers a significant advancement for protein analysis, particularly in biotin-based labeling techniques.
• Its lysine-free design overcomes limitations associated with traditional tags in methods like BioID.
• The GATS tag system provides a sensitive, specific, and low-background alternative for various biochemical and cell biology applications.