Structure at 2.8 Å resolution of F1-ATPase from bovine heart mitochondria (Nature, 1994).

Walker used X-ray crystallography to show the 3D structure of ATP synthase, proving it works like a mechanical rotary engine . This discovery changed how we understand cellular energy. Source: John E. Walker's Nobel Lecture 2. Why We Sleep (Neuroscience)

If you are interested in the Nobel Prize-winning work of , his 1994 paper is a landmark in biology. It revealed that a tiny motor in our cells literally spins to create energy.