Resonance Raman spectroscopy of the neutral radical Trp₃₀₆ in DNA photolyase

The resonance Raman spectrum of the tryptophan neutral radical in a protein, Escherichia coli photolyase, is reported for the first time. The data compare very well to a solution study and computational predictions, and tentative assignments are made for the observed vibrations. This important new result demonstrates the potential of time-resolved resonance Raman spectroscopy as a powerful tool to investigate these radicals in protein electron-transfer processes and in enzymatic reactions in real time.