Daniela Stock is a renowned structural biologist best known for her work on rotary ATPases. She redefined bioenergetics in the late 1990s by solving the X-ray structure of the F1c10 complex of yeast mitochondrial ATP synthase, which provided the first view of a biological rotary motor and introduced the concept of symmetry mismatch and non-integral proton:ATP ratios into the field. Since then she has combined the diverse complementary techniques of electron microscopy, domain antibody technology, mass spectrometry and molecular dynamics to provide a dynamic and almost complete molecular picture of rotary ATPases, leading to major new insights into biological energy conversion.