Type III ATP synthase is a symmetry-deviated dimer that induces membrane curvature through tetramerization.
Flygaard, R.K., Muhleip, A., Tobiasson, V., Amunts, A.(2020) Nat Commun 11: 5342-5342
- PubMed: 33093501 
- DOI: https://doi.org/10.1038/s41467-020-18993-6
- Primary Citation of Related Structures:  
6YNV, 6YNW, 6YNX, 6YNY, 6YNZ, 6YO0 - PubMed Abstract: 
Mitochondrial ATP synthases form functional homodimers to induce cristae curvature that is a universal property of mitochondria. To expand on the understanding of this fundamental phenomenon, we characterized the unique type III mitochondrial ATP synthase in its dimeric and tetrameric form. The cryo-EM structure of a ciliate ATP synthase dimer reveals an unusual U-shaped assembly of 81 proteins, including a substoichiometrically bound ATPTT2, 40 lipids, and co-factors NAD and CoQ. A single copy of subunit ATPTT2 functions as a membrane anchor for the dimeric inhibitor IF 1 . Type III specific linker proteins stably tie the ATP synthase monomers in parallel to each other. The intricate dimer architecture is scaffolded by an extended subunit-a that provides a template for both intra- and inter-dimer interactions. The latter results in the formation of tetramer assemblies, the membrane part of which we determined to 3.1 Å resolution. The structure of the type III ATP synthase tetramer and its associated lipids suggests that it is the intact unit propagating the membrane curvature.
Organizational Affiliation: 
Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165, Solna, Sweden.