Fig. 1: Dependence of ATP/Mg²⁺ in the assembly process of bacterial F-type ATP synthases.

a, b LILBID spectrum of in vitro α and β assembly: the α- (light blue) and β-subunit (dark blue) either without a or with b 2 mM ATP and 2 mM MgCl₂. In presence of ATP/Mg²⁺ the mass spectrum shows the formation of a specific αβ heterodimer assembly, but no higher αβ oligomers. c High-performance Liquid Chromatography (HPLC) of in vitro α (light blue) and β (dark blue) assembly: the addition of 2 mM ATP and 2 mM MgCl₂ to α and β lead to αβ heterodimer formation displayed by a shift from 12.27 min (light green area) to ~11.26 min (light red area). The elution peak at 13.25 min is owing to the high ATP concentration. d Model of bacterial F-type-ATPase: the soluble module F₁ is organized by α- (light blue), β- (dark blue), γ- (dark green), δ- (yellow) and ε-subunit (light green). Source data underlying a–c are provided as a Source Data file.