If the three subunits of a vertebrate ATP synthase are in the following conformation: Open, Loose, and Tight. What would their nucleotide binding states be after 8 protons have passed through the Fo component of ATP synthase from the intermembrane space to the matrix? ATP, Empty, ADP + Pi A D P + P i , Empty, ATP ADP + Pi, ATP, Empty Empty, ADP + Pi, ATP ATP, ADP + Pi, Empty .