Fig. 2.
Light-induced changes in PCB chromophore geometry. The contour plot of the 2D 1H–13C correlation spectra of u-[13C,15N]-PCB-Cph1Δ2 as Pr (red) and Pfr (purple) reveals the intramolecular proximity between protons bound to tetrapyrrole nitrogens (HN21–N24) and chromophore carbons (Dataset S1). Chemical shifts of 13C (as indicated by dashed vertical lines, Pr in red, Pfr in purple) and HN (indicated by solid horizontal lines, Pr in red, Pfr in purple) are in agreement with our previous data (18, 33). Several residue correlations in the close proximity to the chromophore (within a region of approximately 3.5 Å) are also resolved (labeled with Latin capitals A to O, listed in Dataset S2). Spectral regions without resonances, 15–35, 57–88, and 95–109 ppm in the ω2-dimension are omitted. For 1H spectra in the ω1-dimension, only the characteristic spectral region of 8–14 ppm is shown.