Structural dynamics of mitochondrial ATP synthase in Chlamydomonas reinhardtii revealed by in situ CryoET

The turbine dynamics of mitochondrial ATP synthases is an unresolved topic which in situ cryo-ET is poised to answer. Using publicly available tomogram data of vitrified Chlamydomonas reinhardtii cells, a monomer map of ATP synthase was refined to 6.67Å. With extensive heterogeneity analysis, we characterized the in situ conformation states of F1 head, central stalk, and upper peripheral stalk (UPS) individually, and analyzed the by-particle correlation between movement of the different domains, revealing the complex dynamics of the system within cells. While oligomycin sensitivity conferral protein (OSCP) and the UPS were found to bend with F1 head rotation, coupling between the rotation of central stalk and F1 head rotational states, suggested by previous in vitro studies, were not detected from ATP synthase inside mitochondria.