Fig. 3. ATPTT2 anchors IF₁ to the membrane.

a ATPTT2 interacts with the IF₁ C-terminal domains, which dimerizes via their helical hairpins. Close-up view shows the interaction interface between ATPTT2 and IF₁ C-terminal dimer. b IF₁ C-terminal interact via electrostatic interactions on the periphery, and c form a tight hydrophobic core. d Type III ATP synthase dimer with bound intra-dimeric IF₁. The elements forming C-terminal dimer, interact with ATPTT2 and F₁ are indicated in right panel. e porcine type I ATP synthase tetramer (PDB 6J5K) [https://www.rcsb.org/structure/6J5K] with bound inter-dimeric IF₁.