Final answer:
The F1 portion of ATP synthase has a stoichiometry of three alpha and three beta subunits, which work together to synthesize three ATP molecules from ADP and Pi during a full 360° rotation of the F1γ subunit, requiring 12 protons.
Step-by-step explanation:
The stoichiometry of the F1 portion of the ATP synthase complex involves the F1 portion, which has a configuration of three alpha (a) and three beta (ß) subunits arranged alternately, forming a complex denoted as F1(aß)3. This complex is essential for ATP synthesis.
While the F1β subunits are responsible for catalyzing ATP synthesis, the rotation of the F1γ subunit induces conformational changes in these F1ß subunits, facilitating the synthesis process. For a full 360° rotation of the F1 subunit within the F1(aß)3 complex, 12 protons (H+) are required, which results in the production of three ATP molecules from ADP and inorganic phosphate (Pi).