Chai-1 (open complex prediction)

Overview

Chai-1 (Chai Discovery 2024; chaidiscovery/chai-lab) is an open AlphaFold3-style model that predicts multi-entity biomolecular complexes — proteins, small-molecule ligands, and nucleic acids together — from a single typed FASTA. It is particularly used for antibody–antigen and protein–ligand complexes, can run with or without MSAs, and accepts restraints to guide the prediction.

Its niche relative to the other folders: one FASTA describing a mixed assembly, and antibody–antigen in particular. For a ligand co-fold where you specifically want a binding affinity, use alterlab-boltz; for a bare protein, use alterlab-alphafold.

When to Use This Skill