Switchbody, an Antigen-Responsive Enzyme Switch Based on Antibody and Its Working Principle

Area of Science:

• Biotechnology
• Enzyme Engineering
• Biosensor Development

Background:

• Enzyme activity regulation is crucial for biosensing.
• Antibody-based detection methods offer high specificity.
• Combining enzyme activity with antibody specificity presents a novel approach.

Purpose of the Study:

• To develop a novel enzyme switch (Switchbody) for antigen-responsive enzyme regulation.
• To engineer a luciferase-based Switchbody for biosensing applications.
• To elucidate the mechanism of antigen-mediated enzyme activation.

Main Methods:

• Engineering a NanoLuc luciferase fragment (HiBiT)-antibody fusion.
• Utilizing enzyme complementation with LgBiT and furimazine for luminescence detection.
• Employing ELISA, X-ray crystallography, NMR, and MD simulations to study the mechanism.
• Applying the Switchbody platform to label-free IgG antibody detection.

Main Results:

• The luciferase-based Switchbody exhibited dose-dependent enzyme activity increase upon antigen addition.
• Antigen binding was shown to facilitate the interaction between HiBiT and LgBiT.
• Structural and dynamic analyses revealed an antigen-induced disruption of HiBiT trapping within the antibody.
• Label-free detection of IgG antibodies was achieved using the Switchbody platform.

Conclusions:

• The Switchbody platform enables precise, antigen-triggered enzyme activity regulation.
• The
• Trap and Release
• mechanism underlies Switchbody activation.
• This adaptable technology holds promise for developing advanced bioluminescent biosensors and expanding enzyme switching capabilities.