One of the body’s largest macromolecules is the machinery that gloms onto DNA and transcribes it into mRNA, the blueprint for proteins. But the molecule, TFIID, is complex with lots of floppy appendages, which makes it hard to obtain a clear picture of its structure. Using state-of-the-art cryo-electron microscopy detectors and computer analysis, scientists have captured unprecedented detail of how TFIID’s structure changes as it binds to DNA and recruits other proteins.