Scheme 1.

PYP Photocycle Indicating the Dark-Adapted State (pG), the Light-Adapted State (pB), and Photointermediates^a

^aThe isomerization state of the p-coumaric acid chromophore is denoted. In the pH range of 3–10, the pB intermediates have a protonated chromophore, while pG, I₀, and I₁ intermediates are deprotonated.¹⁰-¹² The dashed ellipse shows the photoreversal pathway investigated in this paper, while the pB^trans pathway is based on previous work.¹³