Complex sentence: A proton motive force or pmf drives protons down the gradient, across the membrane through the proton channel of ATP synthase, the resulting current drives ATP synthesis from ADP and inorganic phosphate.
Split into simpler sentences: A proton motive force or pmf drives protons down the gradient (across the membrane) through the proton channel of ATP synthase. The resulting current drives ATP synthesis from ADP and inorganic phosphate.