ATP synthase produces ATP using energy derived from proton gradients created during respiration or photosynthesis. The enzyme consists of two rotary motors, called F₀ and F₁. F₀ is embedded in the membranes of energy-generating cellular structures, such as mitochondria, and is coupled through a common central shaft to F₁, which protrudes from the membrane. Protons pumped through the F₀ rotor are used to drive the rotation of F₁ catalysing the production of ATP from ADP and inorganic phosphate. In 19 April Nature Ryohei Yasuda and colleagues of the Teikyo University Biotechnology Center in Kawasaki, Japan explain the details of the rotation of the F₁ motor (Nature 2001, 410:898-904).