What is Relion?

RELION (REgularized LIkelihood OptimizatioN) is a software program used for cryo-electron microscopy (cryo-EM) single-particle analysis. It employs a Bayesian approach to refine high-resolution 3D structures of biological macromolecules from noisy 2D electron micrographs. It is commonly used to determine the structure of proteins, viruses, and other macromolecular complexes, often achieving near-atomic resolution.