Fig. 5.

Hypothetical ion-coordination structure in the ATP synthase c ring from M. acetivorans. (Top) Snapshot of a molecular dynamics simulation of a model c₄ oligomer in a phospholipid membrane. (Middle) Close-up view of the ion-binding site, in the Na⁺-bound state, in the model based on the c₁₁ ring from I. tartaricus. (Bottom) Close-up view of the ion-binding site, in the H⁺-bound state, in the model based on the c₁₅ ring from S. platensis.