The structure of the central stalk in bovine F1-ATPase at 2.4 Å resolution.

The central stalk in ATP synthase, made of γ, δ and ε subunits in the mitochondrial enzyme, is the key rotary element in the enzyme's catalytic mechanism. The γ subunit penetrates the catalytic (αβ)₃ domain and protrudes beneath it, interacting with a ring of c subunits in the membrane that drives rotation of the stalk during ATP synthesis. In other crystals of F₁-ATPase, the protrusion was disordered, but with crystals of F₁-ATPase inhibited with dicyclohexylcarbodiimide, the complete structure was revealed. The δ and ε subunits interact with a Rossmann fold in the γ subunit, forming a foot. In ATP synthase, this foot interacts with the c-ring and couples the transmembrane proton motive force to catalysis in the (αβ)₃ domain. [ABSTRACT FROM AUTHOR]