The researchers studied how electrons move in the spinach photosystem I reaction center when artificial quinones replace the natural one. They found that most reconstituted quinones quickly oxidized the primary acceptor chlorophyll, preventing charge recombination. Depending on their redox potential, low potential quinones reduced a different acceptor, while high potential ones directly reduced P700. The protein environment shifted the redox potential of the quinones. Reconstituted phylloquinone had a more negative redox potential than Fx. The researchers discussed how these findings contribute to efficient electron transfer in the reaction center.