A community-wide data processing challenge for cryo-electron microscopy.

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Register for the CAHRA Review Workshop from September 16-18, 2026 here.

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Subscribe to the challenge mailing list for announcements here.

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About

Cryo-electron microscopy (cryo-EM) has revolutionized structural biology by enabling high-resolution visualization of dynamic biomolecular complexes. However, a central challenge remains: developing robust methods to model structural heterogeneity — including continuous motions, discrete states, and compositional variations — and to accurately estimate population distributions.

To encourage the development and benchmarking of heterogeneous reconstruction algorithms and workflows, we invite the cryo-EM community to analyze three new curated experimental and synthetic datasets:

• Challenge 1: Compositional Heterogeneity
• Challenge 2: Conformational Heterogeneity + Atomic Modeling
• Challenge 3: Pose Entanglement

We have more than $10,000 in prizes for top-scoring teams and all participants will be invited to the CCP-EM CAHRA Review Workshop in September 2026. If you are interested in participating, please subscribe to our mailing list and join our discussions space. Please share this with others who may be interested. We hope you’ll join us for this year’s challenge!

Timeline

Workshop

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CCP-EM CAHRA Review Workshop

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Datasets

We encourage participants to review both the datasets and submission forms before processing the data.

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Challenge 1: Compositional Heterogeneity

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Challenge 2: Conformational Heterogeneity + Atomic Modeling

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Challenge 3: Pose Entanglement

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Leaderboards