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Finding antibodies in cryo-EM maps with CrAI
Vincent Mallet1, Chiara Rapisarda2, Hervé Minoux2
1LIX, Ecole Polytechnique, IPP Paris, Palaiseau, 91120, France.
Bioinformatics (Oxford, England)
|April 9, 2025
Summary
CrAI is a new machine learning tool that automatically identifies therapeutic antibodies in cryo-electron microscopy (cryo-EM) maps. This efficient method significantly speeds up structural analysis of antibodies, improving drug discovery pipelines.
Area of Science:
- Structural biology
- Computational biology
- Drug discovery
Background:
- Therapeutic antibodies are crucial drugs, refined using structural information.
- Cryo-electron microscopy (cryo-EM) generates 3D maps but can be noisy and artifact-prone.
- Accurate identification of antibodies within cryo-EM maps is essential for interpretation but challenging for existing automated methods.
Purpose of the Study:
- To develop a fully automatic and efficient method for identifying antibodies in cryo-EM maps.
- To overcome the limitations of existing automated methods in terms of accuracy, input requirements, and processing time.
Main Methods:
- Developed CrAI, a novel machine learning approach.
- Leveraged conserved antibody structures and a custom-built database.
- Designed for seamless integration into automated analysis pipelines.
Main Results:
- CrAI is the first fully automatic and efficient method for finding antibodies in cryo-EM maps.
- Predictions are completed in seconds, a significant improvement over hours.
- The method accurately identifies both Fabs and VHHs at resolutions up to 10 Å.
- CrAI demonstrates significantly higher reliability compared to existing approaches.
Conclusions:
- CrAI offers a fast, accurate, and reliable solution for antibody identification in cryo-EM data.
- The method simplifies and accelerates the structural analysis of antibodies.
- CrAI is available as open-source software and a ChimeraX bundle.

