Ground and excited state mapping of plastocyanin from resonance Raman spectra of isotope-labeled proteins

Plastocyanin (Pcy) is a prototypical type 1 copper protein mediating long range electron transfer in photosynthetic plant systems. Resonance Raman (RR) spectra for recombinant poplar Pcy isotopically labeled with cystein-CbetaD(sub2) and (super15)N, are reported. Isotope shifts conform the 400cm(sper1-) vibrations, heavily admixed with cystein internal coordinates. The isotope shifts also allow assignments of high-frequency RR bands to internal His87 and Cys84 vibrations.