Dimeric assembly of F ₁ -like ATPase for the gliding motility of Mycoplasma

Rotary ATPases, including F ₁ F _o - and V/A-ATPases, are molecular motors that exhibit rotational movements for energy conversion ¹ . In the gliding bacterium, Mycoplasma mobile , a dimeric F ₁ -like ATPase forms a chain structure with the glycolytic enzyme, phosphoglycerate kinase (PGK), within the cell ² , which is proposed to drive the bacterial gliding motility ^2–4 . However, the mechanisms of force generation and transmission remain unclear. Here, we present a 3.2 Å resolution structure of the dimeric ATPase complex obtained using electron cryomicroscopy (cryo-EM). Notably, the structure revealed an assembly distinct from that of known dimeric forms of F ₁ F _o -ATPase ⁵ , despite containing conserved F ₁ -ATPase structures. The two ATPase units were interconnected by GliD dimers, previously identified as MMOB1620 ^2,6 . Gliβ, a homologue of the F ₁ -ATPase catalytic subunit ⁶ , exhibited a specific N-terminal region that incorporates PGK into the complex. Structural conformations of the catalytic subunits, catalytically important residues, and nucleotide-binding pattern of the catalytic sites of the ATPase displayed strong similarities to F ₁ -ATPase, suggesting a rotation based on the rotary catalytic mechanism conserved in rotary ATPases ^1,7–10 . Overall, the cryo-EM structure underscores an evolutionary connection in the rotary ATPases and provides insights into the mechanism through which F ₁ -like ATPase drives bacterial gliding motility.