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