Surface-enhanced resonance Raman scattering (SERRS) spectra of phytochrome at 77 K are reported. The spectra reveal significant differences between Pr and Pfr forms of phytochrome. SERRS spectra of C-phycocyanin Z, Z, Z- and Z, Z, E-chromopeptide isomers at 77 K are also reported. The phycocyanin chromopeptide studies are used to provide a basis for interpreting the phytochrome SERRS spectra. The spectra indicate that photoisomerization of chromophores from C-phycocyanin chromopeptides (from a Z, Z, Z to a Z, Z, E configuration) is detectable with SERRS. Comparison of SERRS spectra between the Pr and Pfr forms of 124-kDa phytochrome adsorbed on silver colloids demonstrates that the chromophore undergoes a Z →E isomerization during the Pr →Pfr phototransformation. However, the overall chromophore conformations are likely to be conserved for the native Pr and Pfr phytochrome species.
ASJC Scopus subject areas
- Colloid and Surface Chemistry