Fig. 5.

Ligand-induced changes counteract light-induced structural changes. (A, Left) Superposition of the PPHK-TSD structures in the absence (blue/yellow) and presence of ${\text{BeF}}_3^{-}$ (magenta) reveals large structural changes in subunit A, which extend from the phosphorylation site to the dimer interface, while minimal changes are observed in subunit B. (A, Right) Close-up view shows ligand-induced motions in the conserved residues (Thr89 and Tyr108), along with a displaced loop and nRECα4. (B, Left) Side-by-side comparisons of light-induced motions (green arrows) versus ${\text{BeF}}_3^{-}$-induced changes (magenta arrows) at the dimer interface. (B, Right) Cartoon illustration shows that the ${\text{BeF}}_3^{-}$-induced motions in nRECα4A clash with the light-induced bending of nRECα5B. The reference Pg structure is shown in blue (subunit A) and yellow (subunit B).