Dimeric assembly of F1-like ATPase for the gliding motility ofMycoplasma

Abstract

AbstractRotary ATPases, including F1Fo- and V/A-ATPases, are molecular motors that exhibit rotational movements for energy conversion1. In the gliding bacterium,Mycoplasma mobile, a dimeric F1-like ATPase forms a chain structure with the glycolytic enzyme, phosphoglycerate kinase (PGK), within the cell2, which is proposed to drive the bacterial gliding motility2–4. 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 F1Fo-ATPase5, despite containing conserved F1-ATPase structures. The two ATPase units were interconnected by GliD dimers, previously identified as MMOB16202,6. Gliβ, a homologue of the F1-ATPase catalytic subunit6, 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 F1-ATPase, suggesting a rotation based on the rotary catalytic mechanism conserved in rotary ATPases1,7–10. Overall, the cryo-EM structure underscores an evolutionary connection in the rotary ATPases and provides insights into the mechanism through which F1-like ATPase drives bacterial gliding motility.