Dimeric assembly of F1-like ATPase for the gliding motility of Mycoplasma.

Abstract

Rotary ATPases, including F₁F_O-, V₁V_O-, and A₁A_O-ATPases, are molecular motors that exhibit rotational movements for energy conversion. In the gliding bacterium, Mycoplasma mobile, a dimeric F₁-like ATPase forms a chain structure within the cell, which is proposed to drive the gliding motility. However, the mechanisms of force generation and transmission remain unclear. We determined the electron cryomicroscopy (cryo-EM) structure of the dimeric F₁-like ATPase complex. The structure revealed an assembly distinct from those of dimeric F₁F_O-ATPases. The F₁-like ATPase unit associated by two subunits GliD and GliE was named G₁-ATPase as an R₁ domain of rotary ATPases. G₁-β subunit, a homolog of the F₁-ATPase catalytic subunit, exhibited a specific N-terminal region that incorporates the glycolytic enzyme, phosphoglycerate kinase into the complex. Structural features of the ATPase displayed strong similarities to F₁-ATPase, suggesting a rotation based on the rotary catalytic mechanism. Overall, the cryo-EM structure provides insights into the mechanism through which G₁-ATPase drives the Mycoplasma gliding motility.