Energy powerhouses of cells come into focus

In every kingdom of life, rotary adenosine triphosphate (ATP) synthases and adenosine triphosphatases (ATPases) play key roles in cellular energy generation and release processes. In mitochondria, chloroplasts, and bacteria, F-type (F1Fo) ATP synthases synthesize ATP using energy from a proton gradient. They are also able to perform the reverse process, generating proton gradients by ATP hydrolysis. The related V-type (V1Vo) ATPases have similar structures and serve as proton pumps. Two articles in this issue report structures of membrane-embedded ATP synthases from yeast mitochondria [Srivastava et al. , page 619, ( 1 )] and spinach chloroplasts [Hahn et al. , page 620, ( 2 )]. Together with other recent structures, these articles define core design principles of rotary ATP synthases and ATPases but also highlight organism-specific differences.