Structural Analysis and Optimization of Context-Independent Anti-Hypusine Antibodies

Area of Science:

• Biochemistry
• Structural Biology
• Immunology

Background:

• Hypusination is a unique post-translational modification (PTM) crucial for the function of eukaryotic translation initiation factor 5A (eIF5A).
• Developing tools to study hypusination is essential for understanding its biological roles and identifying novel hypusinated proteins.

Purpose of the Study:

• To identify and characterize context-independent antibodies against hypusine.
• To enhance the affinity of these antibodies for improved detection of hypusinated proteins.
• To elucidate the structural basis of antibody recognition of hypusine.

Main Methods:

• Generation and screening of antibodies for context-independent binding to hypusine.
• Affinity maturation using phage display.
• Crystallography of antibody fragments (Fab) in complex with hypusine- or deoxyhypusine-containing peptides.

Main Results:

• Identified antibodies that bind hypusine with minimal dependence on flanking amino acid sequences.
• Enhanced antibody affinity for hypusine, improving capture of eIF5A.
• Determined crystal structures revealing hypusine binding in a deep pocket formed by VH and VL domains, stabilized by hydrogen bonds.

Conclusions:

• Context-independent anti-hypusine antibodies have been developed and structurally characterized.
• These antibodies demonstrate utility in affinity capture of hypusinated proteins and may facilitate the discovery of novel targets.
• The structural insights provide a foundation for understanding PTM recognition by antibodies.